Charles S. "Charlie" Houston
The founder of the International Hypoxia Symposia and a great personal friend, Charlie Houston was an accomplished mountaineer, physician, scientist and leader of many great medical research projects examining the impact of hypoxia on the human body. His major projects included Operations Everest I and II and the Mt. Logan Project.
In remembrance of Charlie, here is a picture of him, and some links to read more about him and his science.
A nice overview of his professional life on WikiPedia is available here, and obituaries in the Guardian, Alpinist, New York Times, PBS and an obituary by Tom Hornbein in High Altitude Medicine and Biology.
A link to his publications listed in PubMed is here