Permanent Present Tense tells the incredible story of Henry Gustav Molaison, known only as H. M. until his death in 2008. In 1953, at the age of twenty-seven, Molaison underwent a dangerous "psychosurgical" procedure intended to alleviate his debilitating epilepsy. The surgery went horribly wrong, and when Molaison awoke he was unable to store new experiences. For the rest of his life, he would be trapped in the moment. But Molaison's tragedy would prove a gift to humanity. The amazing specificity of his impairment shed new light on the functions and structures of the human brain, revolutionizing neuroscience. Today, the case of H. M. stands as one of the most consequential and widely referenced in this fast-expanding field. Renowned neuroscientist Suzanne Corkin worked with Molaison for nearly five decades. In Permanent Present Tense, she tells the full story of his life and legacy, leading her reader to the cutting edge of neuroscience with great clarity, sensitivity, and grace.