Henry Molaison, known to the world during his lifetime by his initials, H.M., was a man who acquired a profound amnesia following brain surgery to correct his otherwise intrctable severe epilepsy in 1953. He died in late 2008 at age 82. When studied by neuroscientists Brenda Milner and Suzaane Corkin, it was revealed that Henry had an inability to store new memories for facts and events, an anterograde amnesia. However, he could still store other forms of memory such as motor memory, procedural memory and subconscious associations (what we now call non-declarative memory). This was the first clear evidence for multiple memory systems in the brain and has become one of the most famous case-histories in neurology.
If you'd like to listen to me prattle on about H.M. for a few minutes, you can get the "Lifelines" podcast, Episode 17, from the American Physiological Society. My bit starts at 14:54 in the audio file.
Photo from the New York Times obituary.