Guy Christian Collet (1929 – 29 October 2004) was a French scientist, explorer and spelunker who came to live in Brazil after World War II.
He did work in the areas of underground biology, archeology, nutrition techniques in caves, besides having published several books and reports on the subject.
In 1964 he explored Gruta Casa de Pedra, where he first contacted Michel Le Bret and Pierre Martin.
He participated in several speleological expeditions in the State of Goiás and Bahia between 1971 and 1973, mapping the Mangabeira Cave in Bahia along with other scientists, Lapa da Terra Ronca in Goias,[1] São Matheus, São Vicente, Angélica, etc.
He has authored numerous articles in magazines and the "Glossary of Speleological Terms", besides being a special lecturer at colleges, universities and conferences.