Almost at the same time, the tempter whom Father Gomez was setting out to follow was being tempted herself.

"Thank you, no, no, that's all I need, no more, honestly, thank you," said Dr. Mary Malone to the old couple in the olive grove as they tried to give her more food than she could carry.

They lived here isolated and childless, and they had been afraid of the Specters they'd seen among the silver-gray trees; but when Mary Malone came up the road with her rucksack, the Specters had taken fright and drifted away. The old couple had welcomed Mary into their little vine-sheltered farmhouse, had plied her with wine and cheese and bread and olives, and now didn't want to let her go.

"I must go on," said Mary again, "thank you, you've been very kind - I can't carry - oh, all right, another little cheese - thank you - "

They evidently saw her as a talisman against the Specters. She wished she could be. In her week in the world of Citt¨¤gazze, she had seen enough devastation, enough Specter-eaten adults and wild, scavenging children, to have a horror of those ethereal vampires. All she knew was that they did drift away when she approached; but she couldn't stay with everyone who wanted her to, because she had to move on.

She found room for the last little goat's cheese wrapped in its vine leaf, smiled and bowed again, and took a last drink from the spring that bubbled up among the gray rocks. Then she clapped her hands gently together as the old couple were doing, and turned firmly away and left.

She looked more decisive than she felt. The last communication with those entities she called shadow particles, and Lyra called Dust, had been on the screen of her computer, and at their instruction she had destroyed that. Now she was at a loss. They'd told her to go through the opening in the Oxford she had lived in, the Oxford of Will's world, which she'd done - to find herself dizzy and quaking with wonder in this extraordinary other world. Beyond that, her only task was to find the boy and the girl, and then play the serpent, whatever that meant.

So she'd walked and explored and inquired, and found nothing. But now, she thought, as she turned up the little track away from the olive grove, she would have to look for guidance.

Once she was far enough away from the little farmstead to be sure she wouldn't be disturbed, she sat under the pine trees and opened her rucksack. At the bottom, wrapped in a silk scarf, was a book she'd had for twenty years: a commentary on the Chinese method of divination, the I Ching.

She had taken it with her for two reasons. One was sentimental: her grandfather had given it to her, and she had used it a lot as a schoolgirl. The other was that when Lyra had first found her way to Mary's laboratory, she had asked: "What's that?" and pointed to the poster on the door that showed the symbols from the I Ching; and shortly afterward, in her spectacular reading of the computer, Lyra had learned (she claimed) that Dust had many other ways of speaking to human beings, and one of them was the method from China that used those symbols.

So in her swift packing to leave her own world, Mary Malone had taken with her the Book of Changes, as it was called, and the little yarrow stalks with which she read it. And now the time had come to use them.

She spread the silk on the ground and began the process of dividing and counting, dividing and counting and setting aside, which she'd done so often as a passionate, curious teenager, and hardly ever since. She had almost forgotten how to do it, but she soon found the ritual coming back, and with it a sense of that calm and concentrated attention that played such an important part in talking to the Shadows.

Eventually she came to the numbers that indicated the hexagram she was being given, the group of six broken or unbroken lines, and then she looked up the meaning. This was the difficult part, because the Book expressed itself in such an enigmatic style.

She read:

Turning to the summit

For provision of nourishment

Brings good fortune.

Spying about with sharp eyes

Like a tiger with insatiable craving.

That seemed encouraging. She read on, following the commentary through the mazy paths it led her on, until she came to: Keeping still is the mountain; it is a bypath; it means little stones, doors, and openings.

She had to guess. The mention of "openings" recalled the mysterious window in the air through which she had entered this world; and the first words seemed to say that she should go upward.

Both puzzled and encouraged, she packed the book and the yarrow stalks away and set off up the path.

Four hours later she was very hot and tired. The sun was low over the horizon. The rough track she was following had petered out, and she was clambering with more and more discomfort among tumbled boulders and smaller stones. To her left the slope fell away toward a landscape of olive and lemon groves, of poorly tended vineyards and abandoned windmills, lying hazy in the evening light. To her right a scree of small rocks and gravel sloped up to a cliff of crumbling limestone. Wearily she hoisted her rucksack again and set her foot on the next flat stone - but before she even transferred her weight, she stopped. The light was catching something curious, and she shaded her eyes against the glare from the scree and tried to find it again.

And there it was: like a sheet of glass hanging unsupported in the air, but glass with no attention-catching reflections in it, just a square patch of difference. And then she remembered what the I Ching had said: a bypath... little stones, doors, and openings.

It was a window like the one in Sunderland Avenue in Oxford. She could only see it because of the light: with the sun any higher it probably wouldn't show up at all.

She approached the little patch of air with passionate curiosity, because she hadn't had time to look at the first one: she'd had to get away as quickly as possible. But she examined this one in detail, touching the edge, moving around to see how it became invisible from the other side, noting the absolute difference between this and that, and found her mind almost bursting with excitement that such things could be.

The knife bearer who had made it, at about the time of the American Revolution, had been too careless to close it, but at least he'd cut through at a point very similar to the world on this side: next to a rock face. But the rock on the other side was different, not limestone but granite, and as Mary stepped through into the new world she found herself not at the foot of a towering cliff but almost at the top of a low outcrop overlooking a vast plain.

It was evening here, too, and she sat down to breathe the air and rest her limbs and taste the wonder without rushing.

Wide golden light, and an endless prairie or savanna, like nothing she had ever seen in her own world. To begin with, although most of it was covered in short grass in an infinite variety of buff-brown-green-ocher-yellow-golden shades, and undulating very gently in a way that the long evening light showed up clearly, the prairie seemed to be laced through and through with what looked like rivers of rock with a light gray surface.

And secondly, here and there on the plain were stands of the tallest trees Mary had ever seen. Attending a high-energy physics conference once in California, she had taken time out to look at the great redwood trees, and marveled; but whatever these trees were, they would have overtopped the redwoods by half again, at least. Their foliage was dense and dark green, their vast trunks gold-red in the heavy evening light.

And finally, herds of creatures, too far off to see distinctly, grazed on the prairie. There was a strangeness about their movement that she couldn't quite work out.

She was desperately tired, and thirsty and hungry besides. Somewhere nearby, though, she heard the welcome trickle of a spring, and only a minute later she found it: just a seepage of clear water from a mossy fissure, and a tiny stream that led away down the slope. She drank long and gratefully, and filled her bottles, and then set about making herself comfortable, for night was falling rapidly.

Propped against the rock, wrapped in her sleeping bag, she ate some of the rough bread and the goat's cheese, and then fell deeply asleep.

She awoke with the early sun full in her face. The air was cool, and the dew had settled in tiny beads on her hair and on the sleeping bag. She lay for a few minutes lapped in freshness, feeling as if she were the first human being who had ever lived.

She sat up, yawned, stretched, shivered, and washed in the chilly spring before eating a couple of dried figs and taking stock of the place.

Behind the little rise she had found herself on, the land sloped gradually down and then up again; the fullest view lay in front, across that immense prairie. The long shadows of the trees lay toward her now, and she could see flocks of birds wheeling in front of them, so small against the towering green canopy that they looked like motes of dust.

Loading her rucksack again, she made her way down onto the coarse, rich grass of the prairie, aiming for the nearest stand of trees, four or five miles away.

The grass was knee-high, and growing among it were low-lying bushes, no higher than her ankles, of something like juniper; and there were flowers like poppies, like buttercups, like cornflowers, giving a haze of different tints to the landscape; and then she saw a large bee, the size of the top segment of her thumb, visiting a blue flower head and making it bend and sway. But as it backed out of the petals and took to the air again, she saw that it was no insect, for a moment later it made for her hand and perched on her finger, dipping a long needle-like beak against her skin with the utmost delicacy and then taking flight again when it found no nectar. It was a minute hummingbird, its bronze-feathered wings moving too fast for her to see.

How every biologist on earth would envy her if they could see what she was seeing!

She moved on and found herself getting closer to a herd of those grazing creatures she had seen the previous evening, whose movement had puzzled her without her knowing why. They were about the size of deer or antelopes, and similarly colored, but what made her stop still and rub her eyes was the arrangement of their legs. They grew in a diamond formation: two in the center, one at the front, and one under the tail, so that the animals moved with a curious rocking motion. Mary longed to examine a skeleton and see how the structure worked.

For their part, the grazing creatures regarded her with mild, incurious eyes, showing no alarm. She would have loved to go closer and take time to look at them, but it was getting hot, and the shade of the great trees looked inviting; and there was plenty of time, after all.

Before long she found herself stepping out of the grass onto one of those rivers of stone she'd seen from the hill: something else to wonder at.

It might once have been some kind of lava-flow. The underlying color was dark, almost black, but the surface was paler, as if it had been ground down or worn by crushing. It was as smooth as a stretch of well-laid road in Mary's own world, and certainly easier to walk on than the grass.

She followed the one she was on, which flowed in a wide curve toward the trees. The closer she got, the more astounded she was by the enormous size of the trunks - as wide, she estimated, as the house she lived in, and as tall - as tall as... She couldn't even make a guess.

When she came to the first trunk, she rested her hands on the deeply ridged red-gold bark. The ground was covered ankle-deep in brown leaf skeletons as long as her hand, soft and fragrant to walk on. She was soon surrounded by a cloud of midgelike flying things, as well as a little flock of the tiny hummingbirds, a yellow butterfly with a wingspread as broad as her hand, and too many crawling things for comfort. The air was full of humming and buzzing and scraping.

She walked along the floor of the grove feeling much as if she were in a cathedral: there was the same stillness, the same sense of upwardness in the structures, the same awe within herself.

It had taken her longer than she thought it would to walk here. It was getting on toward midday, for the shafts of light coming down through the canopy were almost vertical. Drowsily Mary wondered why the grazing creatures didn't move under the shade of the trees during this hottest part of the day.

She soon found out.

Feeling too hot to move any farther, she lay down to rest between the roots of one of the giant trees, with her head on her rucksack, and fell into a doze.

Her eyes were closed for twenty minutes or so, and she was not quite asleep, when suddenly, from very close by, there came a resounding crash that shook the ground.

Then came another. Alarmed, Mary sat up and gathered her wits, and saw a movement that resolved itself into a round object, about three feet across, rolling along the ground, coming to a halt, and falling on its side.

And then another fell, farther off; she saw the massive thing descend, and watched it crash into the buttress-like root of the nearest trunk and roll away.

The thought of one of those things falling on her was enough to make her take her rucksack and run out of the grove altogether. What were they? Seedpods?

Watching carefully upward, she ventured under the canopy again to look at the nearest of the fallen objects. She pulled it upright and rolled it out of the grove, and then laid it on the grass to look at it more closely.

It was perfectly circular and as thick as the width of her palm. There was a depression in the center, where it had been attached to the tree. It wasn't heavy, but it was immensely hard and covered in fibrous hairs, which lay along the circumference so that she could run her hand around it easily one way but not the other. She tried her knife on the surface; it made no impression at all.

Her fingers seemed smoother. She smelled them; there was a faint fragrance there, under the smell of dust. She looked at the seedpod again. In the center there was a slight glistening, and as she touched it again, she felt it slide easily under her fingers. It was exuding a kind of oil.

Mary laid the thing down and thought about the way this world had evolved.

If her guess about these universes was right, and they were the multiple worlds predicted by quantum theory, then some of them would have split off from her own much earlier than others. And clearly in this world evolution had favored enormous trees and large creatures with a diamond-framed skeleton.

She was beginning to see how narrow her scientific horizons were. No botany, no geology, no biology of any sort - she was as ignorant as a baby.

And then she heard a low thunder-like rumble, which was hard to locate until she saw a cloud of dust moving along one of the roads - toward the stand of trees, and toward her. It was about a mile away, but it wasn't moving slowly, and all of a sudden she felt afraid.

She darted back into the grove. She found a narrow space between two great roots and crammed herself into it, peering over the buttress beside her and out toward the approaching dust cloud.

What she saw made her head spin. At first it looked like a motorcycle gang. Then she thought it was a herd of wheeled animals. But that was impossible. No animal could have wheels. She wasn't seeing it. But she was.

There were a dozen or so. They were roughly the same size as the grazing creatures, but leaner and gray-colored, with horned heads and short trunks like elephants'. They had the same diamond-shaped structure as the grazers, but somehow they had evolved, on their front and rear single legs, a wheel.

But wheels did not exist in nature, her mind insisted; they couldn't; you needed an axle with a bearing that was completely separate from the rotating part, it couldn't happen, it was impossible -

Then, as they came to a halt not fifty yards away, and the dust settled, she suddenly made the connection, and she couldn't help laughing out loud with a little cough of delight.

The wheels were seedpods. Perfectly round, immensely hard and light - they couldn't have been designed better. The creatures hooked a claw through the center of the pods with their front and rear legs, and used their two lateral legs to push against the ground and move along. While she marveled at this, she was also a little anxious, for their horns looked formidably sharp, and even at this distance she could see intelligence and curiosity in their gaze.

And they were looking for her.

One of them had spotted the seedpod she had taken out of the grove, and he trundled off the road toward it. When he reached it, he lifted it onto an edge with his trunk and rolled it over to his companions.

They gathered around the pod and touched it delicately with those powerful, flexible trunks, and she found herself interpreting the soft chirrups and clicks and hoots they were making as expressions of disapproval. Someone had tampered with this: it was wrong.

Then she thought: I came here for a purpose, although I don't understand it yet. Be bold. Take the initiative. So she stood up and very self-consciously called:

"Over here. This is where I am. I looked at your seedpod. I'm sorry. Please don't harm me."

Instantly their heads snapped around, trunks held out, glittering eyes facing forward. Their ears had all flicked upright.

She stepped out of the shelter of the roots and faced them directly. She held out her hands, realizing that such a gesture might mean nothing to creatures with no hands themselves. Still, it was all she could do. Picking up her rucksack, she walked across the grass and stepped onto the road.

Close up - not five steps away - she could see much more about their appearance, but her attention was held by something lively and aware in their gaze, by an intelligence. These creatures were as different from the grazing animals nearby as a human was from a cow.

Mary pointed to herself and said, "Mary."

The nearest creature reached forward with its trunk. She moved closer, and it touched her on the breast, where she had pointed, and she heard her voice coming back to her from the creature's throat: "Merry."

"What are you?" she said.

"Watahyu?" the creature responded.

All she could do was respond. "I am a human," she said.

"Ayama yuman," said the creature, and then something even odder happened: the creatures laughed.

Their eyes wrinkled, their trunks waved, they tossed their heads - and from their throats came the unmistakable sound of merriment. She couldn't help it: she laughed, too.

Then another creature moved forward and touched her hand with its trunk. Mary offered her other hand as well to its soft, bristled, questing touch.

"Ah," she said, "you're smelling the oil from the seedpod..."

"Seepot," said the creature.

"If you can make the sounds of my language, we might be able to communicate, one day. God knows how. Mary," she said, pointing to herself again.

Nothing. They watched. She did it again: "Mary."

The nearest creature touched its own breast with its trunk and spoke. Was it three syllables, or two? The creature spoke again, and this time Mary tried hard to make the same sounds: "Mulefa," she said tentatively.

Others repeated, "Mulefa " in her voice, laughing, and even seemed to be teasing the creature who had spoken. "Mulefa! " they said again, as if it were a fine joke.

"Well, if you can laugh, I don't suppose you'll eat me," Mary said. And from that moment, there was an ease and friendliness between her and them, and she felt nervous no more.

And the group itself relaxed: they had things to do, they weren't roaming at random. Mary saw that one of them had a saddle or pack on its back, and two others lifted the seedpod onto it, making it secure by tying straps around it, with deft and intricate movements of their trunks. When they stood still, they balanced with their lateral legs, and when they moved, they turned both front and back legs to steer. Their movements were full of grace and power.

One of them wheeled to the edge of the road and raised its trunk to utter a trumpeting call. The herd of grazers all looked up as one and began to trot toward them. When they arrived, they stood patiently at the verge and let the wheeled creatures move slowly through them, checking, touching, counting.

Then Mary saw one reach beneath a grazer and milk it with her trunk; and then the wheeled one rolled over to her and raised her trunk delicately to Mary's mouth.

At first she flinched, but there was an expectation in the creature's eye, so she came forward again and opened her lips.

The creature expressed a little of the sweet, thin milk into her mouth, watched her swallow, and gave her some more, again and again. The gesture was so clever and kindly that Mary impulsively put her arms around the creature's head and kissed her, smelling the hot, dusty hide and feeling the hard bones underneath and the muscular power of the trunk.

Presently the leader trumpeted softly and the grazers moved away. The mulefa were preparing to leave. She felt joy that they had welcomed her, and sadness that they were leaving; but then she felt surprise as well.

One of the creatures was lowering itself, kneeling down on the road, and gesturing with its trunk, and the others were beckoning and inviting her... No doubt about it: they were offering to carry her, to take her with them.

Another took her rucksack and fastened it to the saddle of a third, and awkwardly Mary climbed on the back of the kneeling one, wondering where to put her legs - in front of the creature's, or behind? And what could she hold on to?

But before she could work it out, the creature had risen, and the group began to move away along the highway, with Mary riding among them.