He instructed Hannibal in mathematics privately, as the lessons had reached a level inaccessible to the others.

Among Mr. Jakov's books was a copy bound in leather of Christiaan Huyghens ' Treatise on Light, and Hannibal was fascinated with it, with following the movement of Huyghens ' mind, feeling him moving toward discovery. He associated the Treatise on Light with the glare of the snow and the rainbow distortions in the old windowpanes. The elegance of Huyghens ' thought was like the clean and simplified lines of winter, the structure under the leaves. A box opening with a click and inside, a principle that works every time. It was a dependable thrill, and he had been feeling it since he could read.

Hannibal Lecter could always read, or it seemed that way to Nanny. She read to him for a brief period when he was two, often from a Brothers Grimm illustrated with woodcuts where everyone had pointed toenails. He listened to Nanny reading, his head lolling against her while he looked at the words on the page, and then she found him at it by himself, pressing his forehead to the book and then pushing up to focal distance, reading aloud in Nanny's accent.

Hannibal 's father had one salient emotion-curiosity. In his curiosity about his son, Count Lecter had the houseman pull down the heavy dictionaries in the castle library. English, German, and the twenty-three volumes of the Lithuanian dictionary, and then Hannibal was on his own with the books.

When he was six, three important things happened to him.

First he discovered Euclid 's Elements, in an old edition with hand-drawn illustrations. He could follow the illustrations with his finger, and put his forehead against them.

That fall he was presented with a baby sister, Mischa. He thought Mischa looked like a wrinkled red squirrel. He reflected privately that it was a pity she did not get their mother's looks.

Usurped on all fronts, he thought how convenient it would be if the eagle that sometimes soared over the castle should gather his little sister up and gently transport her to some happy peasant home in a country far away, where the residents all looked like squirrels and she would fit right in. At the same time, he found he loved her in a way he could not help, and when she was old enough to wonder, he wanted to show her things, he wanted her to have the feeling of discovery.

Also in the year Hannibal was six, Count Lecter found his son determining the height of the castle towers by the length of their shadows, following instructions which he said came directly from Euclid himself. Count Lecter improved his tutors then-within six weeks arrived Mr. Jakov, a penniless scholar from Leipzig.

Count Lecter introduced Mr. Jakov to his pupil in the library and left them. The library in warm weather had a cold-smoked aroma that was ingrained in the castle's stone.

"My father says you will teach me many things."

"If you wish to learn many things, I can help you."

"He tells me you are a great scholar."

"I am a student."

"He told my mother you were expelled from the university."

"Yes."

"Why?"

"Because I am a Jew, an Ashkenazi Jew to be precise."

"I see. Are you unhappy?"

"To be a Jew? No, I'm glad."

"I meant are you unhappy to be out of school?"

"I am glad to be here."

"Do you wonder if I am worth your time?"

"Every person is worth your time, Hannibal. If at first appearance a person seems dull, then look harder, look into him."

"Did they put you in the room with an iron grate over the door?"

"Yes, they did."

"It doesn't lock anymore."

"I was pleased to see that."

"That's where they kept Uncle Elgar," Hannibal said, aligning his pens in a row before him. "It was in the 1880s, before my time. Look at the windowpane in your room. It has a date he scratched with a diamond into the glass. These are his books."

A row of immense leather tomes occupied an entire shelf. The last one was charred.

"The room will have a smoky smell when it rains. The walls were lined with hay bales to muffle his utterances."

"Did you say his utterances?"

"They were about religion, but-do you know the meaning of 'lewd' or lewdness'?"

"Yes."

"I'm not clear on it myself, but I believe it means the sort of thing one wouldn't say in front of Mother."

"That's my understanding of it as well," Mr. Jakov said.

"If you'll look at the date on the glass, it's exactly the day direct sunlight reaches his window every year."

"He was waiting for the sun."

"Yes, and that's the day he burned up in there. As soon as he got sunlight, he lit the hay with the monocle he wore as he composed these books."

Hannibal further acquainted his tutor with Lecter Castle with a tour of the grounds. They passed through the courtyard, with its big block of stone. A hitching ring was in the stone and, in its flat top, the scars of an axe.

"Your father said you measured the height of the towers."

"Yes."

"How high are they?"

"Forty meters, the south one, and the other is a half-meter shorter."

"What did you use for a gnomon?"

"The stone. By measuring the stone's height and its shadow, and measuring the shadow of the castle at the same hour."

"The side of the stone is not exactly vertical."

"I used my yo-yo as a plumb."

"Could you take both measurements at once?"

"No, Mr. Jakov."

"How much error might you have from the time between the shadow measurements?"

"A degree every four minutes as the earth turns. It's called the Ravenstone. Nanny calls it the Rabenstein. She is forbidden to seat me on it."

"I see," Mr. Jakov said. "It has a longer shadow than I thought."

They fell into a pattern of having discussions while walking and Hannibal, stumping along beside him, watched his tutor adjust to speaking to someone much shorter. Often Mr. Jakov turned his head to the side and spoke into the air above Hannibal, as though he had forgotten he was talking with a child. Hannibal wondered if he missed walking and talking with someone his own age.

Hannibal was interested to see how Mr. Jakov got along with the houseman, Lothar, and Berndt the hostler. They were bluff men and shrewd enough, good at their jobs. But theirs was a different order of mind.

Hannibal saw that Mr. Jakov made no effort to hide his mind, or to show it off, but he never pointed it directly at anyone. In his free time, he was teaching them how to survey with a makeshift transit. Mr. Jakov took his meals with Cook, from whom he extracted a certain amount of rusty Yiddish, to the surprise of the family.

The parts of an ancient catapult used by Hannibal the Grim against the Teutonic Knights were stored in a barn on the property, and on Hannibal's birthday Mr. Jakov, Lothar and Berndt put the catapult together, substituting a stout new timber for the throwing arm. With it they threw a hogshead of water higher than the castle, it falling to burst with a wonderful explosion of water on the far bank of the moat that sent the wading birds flapping away.

In that week, Hannibal had the keenest single pleasure of his childhood.

As a birthday treat Mr. Jakov showed him a non-mathematical proof of the Pythagorean theorem using tiles and their impression on a bed of sand.

Hannibal looked at it, walked around it. Mr. Jakov lifted one of the tiles and raised his eyebrows, asking if Hannibal wanted to see the proof again. And Hannibal got it. He got it with a rush that felt like he was being launched off the catapult.

Mr. Jakov rarely brought a textbook to their discussions, and rarely referred to one. At the age of eight, Hannibal asked him why.

"Would you like to remember everything?" Mr. Jakov said.

"Yes."

"To remember is not always a blessing."

"I would like to remember everything."