Say the letters “H M” to a neuroscientist, and chances are he or she will nod knowingly. H.M. was a man who died in 2008. His full name was Henry Molaison, and a surgical procedure in the 1950s left him without much of his memory. Studies on his mind laid the groundwork for our understanding of memory today. In tomorrow’s issue of the Wall Street Journal, I review a remarkable biography of Molaison, written by MIT neuroscientist Suzanne Corkin, who studied him from their first meeting in 1962 till his death–and beyond. While it’s not a perfect, it is–pardon the pun–a memorable one.