This article traces the history of Jack London’s business relationships with The Cosmopolitan magazine, which are reconstructed on the material of the scientifi cally commented The Letters of Jack London (1988). In this relationship London originally acted as an independent writer, who was attracted by the maximum royalties paid by The Cosmopolitan, then he began writing by request of the magazine’s editors, and fi nally signed a permanent contract with them, in which, contrary to his expectations, he was forced to perform the functions of a literary day-labourer.