The Heritage We Defend reviews the political and theoretical disputes inside the Fourth International, the international Marxist movement founded by Leon Trotsky in 1938. It is a reply to former WRP General Secretary Michael Banda's document "27 Reasons why the International Committee Should be Buried Forthwith and the Fourth International Built. This work also contains a detailed assessment of the political contribution and evolution of James P. Cannon, Trotsky's most important co-thinker in the US, and the evolution of the U.S. Socialist Workers Party more generally.

This 2018 edition of the foundational 1988 work by David North, chairman of the International Editorial Board of the World Socialist Web Site, contains a new preface, photo section and an extensive glossary.