Despite an annoying hero who should have grown up by the 15th book in a popular and long-running series (The Dante Game; etc.), Langton delivers another solid effort. As Charlottesville, Va., prepares for a presidential visit celebrating the anniversary of Thomas Jefferson's election as U.S. president, a serial killer in the area is stalking female victims. At Monticello newly hired researcher Fern Fisher is trying to burnish Jefferson's tarnished reputation, while in the surrounding woods discontented med student Tom Dean has illegally set up camp. Tom joins Fern in her researches, arguing that sponsoring Lewis and Clark's Voyage of Discovery was Jefferson's only real achievement. As the two pursue their shared interest, the killer sets his sights on Fern. When the body of another woman turns up, Tom faces a murder charge. Enter sleuthing professor Homer, who undertakes to clear Tom's name and expose the real killer. The plot is as twisting and complex as the upper reaches of the Missouri River, and the book teams with likable characters, with two exceptions--the murderer and Homer, with his bag of quirks and foibles. Fortunately, the strong historical background, which includes descriptions of Jefferson's innovations at his home and chapter headings from the explorers' journals, more than compensates. The author's own pen-and-ink drawings add to the charm. (Feb. 19) Forecast: Langton received a Lifetime Achievement Award at the Bouchercon 2000 mystery convention. If booksellers publicize that honor, and give healthy display to this book, which carries a nifty cover of Jefferson looking downright puzzled, this could prove to be Langton's most popular Homer Kelly to date.