In the meantime, Jennet's father, along with her brother Dunstan, travels around England tracking down witches and bringing them to trial. Isobel's intellectual pursuits soon draw unwelcome attention from the vicar who is the father of her other pupil, Elinor Mapes, and Walter Sterne, upon returning home, does not hesitate to have his own sister-in-law tried for sorcery.

Jennet sets off on a dangerous journey to Cambridge in the hope of finding Isaac Newton and convincing the great man to testify in her aunt's defense, for as Newton has written, "Wicked Spirits enjoy no essential Existence." Although she fails in that mission, Jennet finds her own mission in life; she will do whatever she can to bring an end to the Parliamentary Witchcraft Act of 1604.

Her quest takes her from England to the New World, where her adventures include becoming a captive of Indians, acquiring and losing a couple of husbands, surviving a shipwreck and encountering pirates and a utopian community of runaway slaves. Along the way, she meets a rich cast of both fictional and historical characters, among them the young Ben Franklin, the elderly Isaac Newton, Pussough and Okommaka of the Nimacooks, Abigail Williams of Salem, the Baron de Montesquieu and Barnaby Cavendish, curator of the Museum of Wondrous Prodigies.

Her life is rich in intellectual adventures as well, for one of the tools Jennet hopes to use against witchfinders is her book The Sufficiency of the World, the product of her own experiments and scholarly explorations. Her fight against superstition eventually leads Jennet to risk her own life in that battle by having herself put on trial for witchcraft, with her own brother as one of her prosecutors.

A diverting and imaginative novel

If James Morrow had done no more than written a novel that was the equal of Blameless in Abaddon or Only Begotten Daughter, to name only two of his previous works (discerning readers will by now have collected them all), he would, once again, have delivered a book that would reward any reader looking for intelligence, wit, humor and an affectionate but biting satirical take on his fellow human beings. But in The Last Witchfinder, he surpasses the high standard he has already set for himself.

This novel combines the conventions of historical fiction, alternative history, speculative fiction and picaresque 18th-century novels in a narrative that will make readers both laugh out loud and be moved close to tears, while being constantly challenged and diverted by copious references to scientific thought, colonial American culture, Western philosophy and the kinds of superstitious thinking that remain rampant today. Morrow also accomplishes the trick of making every line of The Last Witchfinder not only a treat in itself but also an essential part of the story; this is a compulsively readable book with a style that should be savored. Readers are likely to be torn between the strong desire to know what happens next and wanting to slow down enough to enjoy every piece of wit or to test themselves on how many of the references they can grasp.

Morrow, appropriately, remains true to the conventions of the 18th-century novel by having his narrator address the reader directly from time to time. In a stroke of inspiration, he has made that narrator Newton's Mathematical Principles of Natural Philosophy. Readers of science fiction may view this narrator in the form of the Principia as a kind of artificial intelligence, and all readers should recognize this literal embodiment of a truth known to all lovers of reading: that books are indeed friends and often a more enduring part of individual lives than any number of other distractions.

Some readers may wonder if Morrow's novel is actually science fiction (or speculative fiction), although such concerns should not inhibit them from thoroughly enjoying a book that is so satisfying on so many levels. The fact is that, in its embrace of rational thought and tribute to the complex and earthy mix that is human life, The Last Witchfinder is a moving evocation of science fiction's roots, roots that have lately been obscured by the blossoming of fantasy, and a reminder that the battle Jennet Stearne has to fight remains with us.