James Morrow's The Last Witchfinder (William Morrow, 2006) is, without question, one of the most enjoyable novels I've read this year. A bit fantastical, it offers a nice escape from the bonds of traditional literature through a fascinating narrative structure that I was delighted to see employed effectively (done poorly, this book would easily have been a horrendous mess).
The novel, you see, is written by Newton's Principia Mathematica, who occasionally breaks into the narrative to offer super-textual commentary (such as a very funny explanation of how it is that existing books, not human authors, create new works of literature and prose ... and Hallmark cards) - think Fforde plus Eco with a hint of Borges and a healthy dash of Neal Stephenson.
At the core of the novel's main plot is Jennet Stearne, daughter and sister to witchfinders, niece to a woman wrongly executed as a witch whose dying wish was that Jennet disprove the supernatural basis of those events people interpreted as sorcery. A task easier said than done, but our heroine accepts the challenge. Naturally, the path is neither short nor smooth.
With appearances from Isaac Newton, Ben Franklin, Baron Montesquieu, Abigail Williams of Salem infamy and other characters factual and fictional, The Last Witchfinder is a rollicking book-trip through the eighteenth-century world where rationality and revelation duked it out (just as the Principia and his archnemesis the Malleus Maleficarum engage in a tangential final proxy-battle in the streets of New York).
You've got to read it to believe it. Aside from a few minor anachronisms, Morrow (er, sorry, Principia) has penned a fine tale.