Synopsis The book is an authentic monograph on Atattvabhinivesha. The Atattvabhinivesha is a disease of perplexed identity in the Charak Samhita. The confusion creates due to two different commentaries on it by Chakrapani, the great commentator of Charak Samhita. While in Sutrasthana he described Atattvabhinivesha as 'Eko Mahagada' means the immense disease; he straightway refused its description in Chikitsa Sthana saying it as 'Anarsha' means edition of its text by someone else in later period. All the other scholars of Ayurveda of Samhita period including Sushruta and Vagbhatta did not describe this disease. Owing to this confusion and lack of detailed description of this disease, its thorough knowledge is the need of time since long. This book fulfills this need. This book concludes that Atattvabhinivesha is a minor psychological ailment and it resembles with neurotic disorders of modern psychiatry particularly anxiety states. This monograph carries findings of a scientifically designed clinical study, which provide authenticity to the outcome. This book will be a landmark in developing better understanding of psychiatry according to Ayurveda.