Contemplating whether the government could censor imams whose preaching might incite terrorism, Harvard law professor Dershowitz (Blasphemy) wondered what Thomas Jefferson would say about "where to draw the appropriate line, between dangerous speech and harmful conduct." Dershowitz found an answer in New York's Argosy Bookstore, where he stumbled over a letter written by Jefferson on July 3, 1801, addressing the limits of free speech, especially religious and political speech. Based in part on his reading of Jefferson, Dershowitz concludes that we ought not to censor the speech of even the most violent religious leaders. Echoing Jefferson, he says that liberty is dangerous and adds that in any case censorship would not prevent either violence or incitement to it. This book is not without its annoyances: it opens with a self-indulgent tour through the many objects Dershowitz likes to collect, from baseball paraphernalia to the odd picture of Abraham Lincoln, and the bulk of Dershowitz's ruminations are cast in a long letter to Jefferson—a distracting device. These meditations from one of our most provocative constitutional scholars may not evoke as much controversy as have his earlier suggestions that there be warrants for interrogators to use torture in limited circumstances, but the main contribution here is the publication of Jefferson's letter. Photos. (Nov.) (Publishers Weekly, September 3, 2007)