Satan has returned to Earth for a sightseeing visit in the form of the American billionaire Henry Wondergood. Accompanied by his faithful demon butler Toppi they head for Rome, but are sidetracked by an unforeseen accident and end up at the home of the inscrutable Thomas Magnus and his divine daughter Maria. As Satan begins to discover the meaning of being a man, the satanic aspects of mankind become ever more apparent to him.

Leonid Andreyev was a Russian author active in the beginning of the twentieth century, famous mostly for his plays and short fiction, and often portrayed as Russia’s equivalent to Edgar Allan Poe. Satan’s Diary was his last work, completed just a few days before his death in 1919. This edition was translated by his previous collaborator Herman Bernstein and published in 1920.