Endocrinology is a branch of biology and medicine dealing with the endocrine system, its diseases and its specific secretions known as hormones. Endocrinology is a text book for all the students of life sciences. This book is prepared based on a decade of experience in the field of endocrinology teaching and research. This book provides ample information regarding basic and applied concepts of endocrinology. This book is divided into 10 prime chapters which provide basic information related to respective topics. The technical term for this physical arrangement is codex (plural, codices). This book covers the concept of general endocrinology, hypothalamus, pituitary hormones, thyroid gland, parathyroid gland, pancreas, stomata statin, adrenal gland, gonadal gland, pineal gland and thymus gland. This book has been structured in such a way without sacrificing the accuracy of information, that students can access information in small, well identifiable steps. Illustration makes the subject more interesting and easy to understand. We hope this book will promote self learning and create interest and will help the students for quick revision for the theoretical aspects for their university as well as competitive examinations.