Paul Broca made the most significant discovery in nineteenth-century human biology when he found that speech resides within the left frontal lobe of the human brain. As a young surgeon working at the hospice at Bic?tre on the outskirts of Paris ? a repository for the criminal, the insane, the indigent, and the sick ? Broca had to overcome derision, acrimony, personal attacks, vindictiveness, and prevailing doctrines before his findings were accepted...