What makes a genius? Eminent personages of the 19th century often left their brains to science. The convoluted gray matter of Lord Byron, Anatole France, William Makepeace Thackery, Walt Whitman, and Charles Babbage was collected and stored in jars, in the hopes of finding what made them so smart. The studies ended unconclusively, but the brains are still locked away in museums and research centers. Brian Burrell, a mathematics lecturer at UMass, describes his visits to these collections in his new book, Postcards from the Brain Museum.