Cobb is best known for his multi-volume work "The People's Armies" (1961), a massive study of the composition and mentality of the Revolution's civilian armed forces. He was a prolific writer of essays from which he fashioned numerous book-length collections about France and its people. Cobb also found much inspiration from his own life, and he composed a multitude of autobiographical writings and personal reflections. Much of his writing went unpublished in his lifetime, and several anthologies were assembled from it by other scholars after his death.