This book looks at multiple personality through the lens of individuality. Each part deals with a specific aspect of multiple personality: personality, double personality, and finally, consciousness and multiple personality. The work of Parts I and III covers a period of eight years. Out of the material accumulated by Dr. Sidis and his collaborators, some experiments and observations of functional psychopathic cases have been utilized in the last part of this volume. The authors note that the case of double personality described in Part II is of great interest and is specially recommended to the reader's attention. This case was investigated in the Pathological Institute of the New York State Hospitals. (PsycINFO Database Record (c) 2004 APA, all rights reserved).