This bibliography includes studies of defense mechanisms, in general, and studies of multiple mechanisms. Defense mechanisms, briefly and simply defined, are the unconscious ego defendants against unpleasure, threat, or anxiety. Sigmund Freud deserves the clinical credit for studying many mechanisms and introducing them in professional literature. The vagaries of studying and researching defense mechanisms are many and varied. In terms of rationale, consider mechanisms and the problems of copying vs. defense, instinctual vicissitude vs. defense, dynamic vs. symptom, specific defense vs. general defense, adaptiveness vs. success, basic (first order) vs. complex (second order), major vs. minor, primary gain vs. secondary gain, conscious vs. unconscious, operation unconscious vs. system unconscious, ego boundary vs. ego, etc. Of course, there is more to defense than defense mechanisms. This bibliography ranges from the mid 1930's to the mid 1960's. (Author)