"Although I cannot tell for certain what sparked my interest in the neural underpinnings of reason, I do know when I became convinced that the traditional views on the nature of rationality could not be correct." Thus begins a book that takes the reader on a journey of discovery, from the story of Phineas Gage, the famous nineteenth-century case of behavioral change that followed brain damage, to the contemporary recreation of Gage's brain; and from the doubts of a young neurologist to a testabl ...