IN THE SEVEN YEARS HAVE ELAPSED SINCE THE PUBLICATION OF THE SECOND EDITION AF ENDOCRINOLOGY AND METABOLISM, THERE HAS BEEN AN ENORMOUS INCREASE IN OUR KNOWLEDGE OF BASIC CONCEPTS OF CELLULAR AND MOLECULAR BIOLOGY, GENETICS, AND INTRACELLULAR SIDNALING MECHANISM. AS A RESULT, OUR UNDERSTANDING OF THE ETIOLOGY AND PATHOPHYSIOLOGY OF ENDOCRINE AND METABOLIC DISORDERS AND OUR APPROACH TO DIAGNOSIS AND TREATMENT HAVE BEEN ADVANCED.