André Level developed an important art collection, capitalizing on his skill as an art critic and dealer. His letters, which are housed at the Getty Research Institute, reflect his early supporter of Matisse and Picasso, and his role as an advisor in the formation of a collection of contemporary art called La Peau de l'Ours. The auction of his collection in 1914 was a major event, and proved to be quite financially successful.
Level, André. Souvenirs d'un collectionneu. Paris, 1959
Fitzgerald, Michael Cowan. "Skin Games," Art in America 80 (February 1992):70-83