Paul Auster's Invisible. The NYT reviewer thinks it's his best.
Richard Flanigan. An Australian writer, a favorite of Reading Matters.
Karen Armstrong's The Case for God.
The Perfect Heresy: The Revolutionary Life and Death of the Medieval Cathars by Stephen O'Shea. Described In the further reading section of A Castle in the Backyard as a short, readable history of the sect and the crusades against it.
The Cave Artists by Ann Sieveking. Also from the further reading section of A Castle in the Backyard.
Archie and Amelie: Love and Madness in the Gilded Age by Donna Lucey
Victorian Internet: The Remarkable Story of the Telegraph and the Nineteenth Century's On-line Pioneers by Tom Standage