October 2000, University of Paris, La Salpêtrière Hospital, Charcot Amphitheater. I was invited to give a short acceptance speech on a subject of my choosing after being awarded the Jean-Louis Signoret Prize. Determined to deliver it in French, I gave it an ambitious title: “Liberté et l’Exécutif du Cerveau.” In less than half an hour I tried to explain that the prefrontal cortex is the cerebral enabler of the human agenda. Further, that the achievement of biological and social goals is the outcome of the competition between demands of internal and external milieus continuously barraging that cortex. Further, that those demands include unconscious ethical imperatives in addition to instinctual urges. Of course, I dutifully cited Claude Bernard and Benjamin Constant. Human liberty, I concluded, is a phenomenon of the brain’s ability to choose, rationally or not, between alternatives of action.

Only after my talk did I realize I had overreached. I had spoken about a sacred French theme in less than perfect French to an intellectual French audience in an august French forum. Now, a dozen years past, this book is an attempt to say all those things better, in English.

What motivates this brain scientist to write about such a lofty theme as human liberty? And what qualifications does he have to do it? He surely must know that the terrain is fraught with pitfalls. Emphatically yes, he knows the dangers. No one has to convince him that those dangers are very real, especially the disdain, or, worse, the implacable wrath, with which modern neuroscience treats the unsuspecting defender of free will.