His main work was Ma Civilisation (1942), illustrated by Lucien Coutaud, which was followed by La Folie Tristan in 1954.
The book was only possible because Xavier Henri Marie de Sade opened the family archive for the first time in four generations.
Lély took over the task of publishing Sade's works from Maurice Heine.
His late work consists of L'Épouse Infidèle (1966) and the dramatic poem Solomonie la Possédée (1979).
Lély was born on 19 March 1904 in Neuilly-sur-Seine and died on 4 June 1985 in Paris.