Hans Hass (1919Ð2013) was an Austrian biologist and underwater diving pioneer. He was known mainly for being among the first scientists to popularise coral reefs, stingrays, octopuses and sharks. He pioneered the making of documentaries filmed underwater and led the development of a type of rebreather. He is also known for his energon theory and his commitment to protecting the environment. Men and Sharks was first published in Zurich in 1949 and then translated into English for this edition in 1954. With 56 b/w photographs.