McDougall reviews Sidis’ book “Multiple personality.” The book mainly concerns the case of Mr. Hanna. He suffered from a complete loss of memory following an accident. He began to have brief snips of his past life, mostly through dreams. He eventually regained his previous memories and was able to also remember his “new” memories. Sidis stated that the case was one of psycho-physiological dissociation. McDougall does not come to the same conclusion of Mr. Hanna’s case as Sidis does. McDougall questions to what extent the treatment brought about Mr. Hanna’s recovery. McDougall briefly covers the other contents of the book.