In 1953, experimental brain surgery was performed on a young man named Henry M. It was a time when lobotomies were in fashion, and Henry's doctors believed that his epilepsy could be cured by a radical operation. Two holes were drilled into Henry's skull above his eyes and through a silver straw the hippocampus - a grayish-pink organ the size and shape of a fist - was sucked out from deep within Henry's brain.

When Henry recovered, it was clear that something had gone terribly wrong. He could talk and read and write. But when asked where he was, or who the people were at his bedside, he did not know. Nurses could speak to him and return a moment later, only to find he had no memory of them.

For decades Henry's guardians at M.I.T.'s clinical research center have shielded him, restricting access to academic researchers. Now, in Memory's Ghost, Philip J. Hilts, one of a relatively small number of people who have spent extended time with Henry, tells Henry's remarkable story. But Henry's story is only part of Memory's Ghost. Memory's Ghost examines as well how great thinkers have understood memory, from Plato and St. Augustine to Proust and William James.

Memory's Ghost explains how memory works and how it doesn't work, how mnemonic devices work, where memory functions are physically located in brain regions, and how the hippocampus - the part of the brain that Henry M. lost - organizes information into memory. Part poetic reflection and philosophical meditation, part popular science and investigative journalism, Memory's Ghost is an intriguing exploration of the mysteries of the mind and of a man whose memory was stolen from him.