We conceptualize this book with the intention of making diagnosis and management of adolescent with irregular period easier for resident and fellows who are beginning their carrier in obstetrics and gynecology. This book is also beneficial for established practitioner to plan the management protocol for patients with PCOS in their early age. There is no substitute to a good and complete clinical examination and the objective of this book is simply to outline the basic investigation that a trainee must learn to master to arrive at the correct clinical diagnosis and to plan future management of the patient. The main author felt while pursuing her residency that there was a lack of a simple yet concise textbook that would give her a outlook on diagnosis and management of adolescent girl with irregular period and risk assessment of insulin resistance as well as metabolic syndrome. The increasing incidence of PCOS in younger age, PCOS patient with infertility, diabetes mellitus and metabolic syndrome issues has pushed us to do study on these patients and to publish it.