Maimonides, mortality and a mysterious death

While there's a touch of Dan Brown derring-do to the novel there is also something of Paulo Coelho's spiritual questing. But Perplexed is essentially its own super-smart and impressive creation - the fourth book by this 36-year-old mother of four, Hebrew scholar and Harvard-educated literature professor.

Dara Horn has spoken of living two lives - family and fiction - and of the contrast between the records we write and our inevitable mortality. "Every human being," her book observes, "becomes the opposite of an archive."

Horn takes her title, of course, from Moses Maimonides's great, 12th century work. And it is apt because his famous oeuvre is all that Josie has for distraction while holed up in a filthy dungeon perfecting her unique computer app for nameless abductors who will surely kill her when the job (a virtual archive of human memory) is done.

For the first time in her golden life, Josie - the brighter, more beloved and beautiful of two sisters - is forced to be still, to contemplate the origins of good and evil, the argument for free will over divine predestination.

What has brought her to this terrifying brink? Had she decided against making the risky but prestigious trip to Egypt, Josie's husband Itamar and strange little daughter Tali might never have had to confront the video of her hanging, lifeless, from a rope… nor take dubious comfort from her jealous sister Judith.

Josie's programme, code-named "Genizah", is one, 21st-century, answer to the philosophical question: What happens to days that disappear?

Solomon Schechter, whose story intertwines with Josie's, provides a different answer. Schechter's outstanding, real-life gift to Jewish memory was his discovery of the Cairo Genizah - a synagogue archive of 300,000 dusty documents illuminating the medieval world.

In a third story-line, Maimonides ponders the loss of his brother David, despatched to India in search of the mysterious plant or herb that might cure the great doctor's most celebrated patient, Saladin.

In the anguish of his bereavement, Maimonides asks if he, or at least his ambition, triggered David's death, or if it was inevitable.

The parallels between these tales of different times invite the thought that maybe the same themes play out again and again down the sweep of the centuries.

As Dara Horn suggests, issues of parental love, favouritism and sibling rivalry have echoed through our history ever since Joseph's brothers threw him in a pit. How many generations have been perplexed by questioning divine matters and plagued by family dysfunction?

Horn's Guide also probes the healing power of forgiveness and concludes that it is contingent upon much more than sheer generosity of spirit.

Madeleine Kingsley is a freelance writer