Brief biography of Hippocrates here.

The whole text of On Airs, Waters and Places (in English) is available here. This work was revolutionary because, instead of ascribing diseases to divine intervention, it discussed their environmental causes.
   Hippocrates is generally considered the 'Father of Medicine', but this shows he can also be considered the 'Father of Environmental Health' and thus he had a direct influence on environmental engineering.   
   Index to other Hippocrates’ works in English (University of Adelaide).