And I read something else," Jacob goes on. "There was this discussion of the story of Cain and Abel, from the Bible. After Cain kills his brother, God says, 'The bloods of your brother call out to me.' Not blood. Bloods. Weird, right? So the Talmud tries to explain it."

"I can explain it," says William. "The scribe was drunk."

"William!" cries Jeanne. "The Bible is written by God!"

"And copied by scribes," the big boy replies. "Who get drunk. A lot. Trust me."

Jacob is laughing. "The rabbis have a different explanation. The Talmud says it's 'bloods' because Cain didn't only spill Abel's blood. He spilled the blood of Abel and all the descendants he never had."

"Huh!"

"And then it says something like, 'Whoever destroys a single life destroys the whole world. And whoever saves a single life saves the whole world."

There are sheep in the meadow beside the road. Gwenforte walks up to the low stone wall, and one sheep--a ram--doesn't run away. They sniff each other's noses. Her white fur beside the ram's wool--two textures, two colors, both called white in our inadequate language.

Jeanne is thinking about something. At last, she shares it. "William, you said that it takes a lifetime to make a book."

"That's right."

"One book? A whole lifetime?"

William nods. "A scribe might copy out a single book for years. An illuminator would then take it and work on it for longer still. Not to mention the tanner who made the parchment, and the bookbinder who stitched the book together, and the librarian who worked to get the book for the library and keep it safe from mold and thieves and clumsy monks with ink pots and dirty hands. And some books have authors, too, like Saint Augustine or Rabbi Yehuda. When you think about it, each book is a lot of lives. Dozens and dozens of them."

Dozens and dozens of lives," Jeanne says. "And each life a whole world."

"We saved five books," says Jacob. "How many worlds is that?"

William smiles. "I don't know. A lot. A whole lot.

Adam Gidwitz