Plucky Charms

One of the figures, pictured with Jews at a Passover Seder, was a black-skinned woman with African features. Who was she? No one knows.

Brooks got to imagine her.

After the Convivencia came the Spanish Inquisition and the expulsions of the Jews from Spain in 1492. Somehow the Haggadah survived. Nothing is known of how this happened, though Brooks says her chapter about it is "true to the details of the Inquisition" because, "sadly and troublingly," the inquisitors kept meticulous records of water torture sessions. (She never expected to open a newspaper and learn "that we were doing essentially the same thing.")

One more small fact: An inscription on the Haggadah by a Catholic priest places the manuscript in Venice in 1609. Brooks imagined the priest's life and -- with the help of a revealing memoir by a Venetian rabbi -- evoked the relations between the Christian city and its Jewish ghetto.

Trying to keep her fictional details as close to reality as possible, Brooks used part of a fellowship year at Harvard's Radcliffe Institute to borrow scholarly expertise.

She took Harvard librarians to tea and was regaled with tales of conservators tracking down clues hidden in manuscripts. She pestered biologist Naomi Pierce to help her invent one particular clue, involving the wing of a butterfly that lives only in Alpine habitats.

Another clue involved a wine stain that would turn out to have blood mixed in it. Brooks spent a happy day spilling liquids on bits of parchment in the conservation lab at Harvard's art museum. "I didn't know where we were going to get blood," conservation specialist Narayan Khandekar recalls, "and she just asked, 'Do you have a scalpel?' " He handed her a No. 11 and she jabbed a finger.

Blood, she learned, leaves a sharper-edged stain than wine.

Meanwhile, she solved the problem of her fictional conservator's voice in the most obvious possible way: She switched her nationality from Bosnian to Australian.

So simple!

Born and raised in Australia herself, Brooks found that Hanna Heath "just jumped onto the page." But conclusions about autobiography would be ill-advised. For one thing, Hanna has the mother from hell -- a high-powered surgeon who mocks her daughter's wimpy career choice -- and her creator wants no confusion on this point.

"She's absolutely not my mother," Brooks says. "My mum and I were always best friends."