Jean Edmond Cyrus Rostand (30 October 1894 – 4 September 1977) was a French biologist, historian of science, and philosopher.

Active as an experimental biologist, Rostand became famous for his work as a science writer, as well as a philosopher and an activist.

He was educated by home tutors and read the works of J. H. Fabre, Claude Bernard and Charles Darwin.

He then examined polydactyly and its induction by chemical agents in frogs and studied the preservation of sperm vitality using glycerine.

[citation needed] Rostand took a special interest in the history of science and especially stressed the slow process by which scientific facts were determined and how they emerged from the interactions of numerous people and highlighted the need for modesty, especially because of the fallibility of individual workers.

After 1922 he set up a laboratory in his home at Ville d’Avray and began to conduct most of his research there, free of institutional demands.