In 1953, Henry Molaison (soon to go down in history as "H.M." to protect his privacy) underwent brain surgery to eliminate the occurrence of dangerous seizures. Following his surgery, two facts became apparent to his doctors:
1) the surgery was successful at eliminating his seizures
2) Mr. Molaison was now incapable of creating new memories
This second realization was a landmark discovery in brain science, and Mr. Molaison consented to tests and observation for the rest of his life which have allowed scientists to develop understanding, proceedures, and techniques that would improve the lives of countless other human beings. (It had been previously thought that memories were created through universal brain processes, but Mr. Molaison's inability to create new memories after the removal of two narrow, inch-long plugs revealed that memories are indead created in very small, distinct areas of the brain. Over time, however, Mr. Molaison was able to become increasingly proficient at new tasks, revealing that an area of the brain completely distinct from the memory-creation areas is instrumental in the learning process.)
Mr. Molaison died on December 2, 2008. On December 2, 2009, Mr. Molaison's unplanned but generous contributions to science and humanity began anew when neuroscientists began slicing, sampling, and mapping his brain in a project that has been dubbed Project H.M.
Even more fascinating - the scientists are chronicalling the historical, painstaking proceedure live online. You can watch their daily progress online at The Brain Observatory website.
If you would like to read more about the project and Mr. Molaison, you can do so here.