This book deals with a vital topic: metabolism in the cells of the body and various disorders due to its imbalance and/or diseases that disrupt the metabolism of the body. The objective of this book was to collect and compile up-to-date information from reputed researchers in their respective fields to disseminate the latest information about topics that have profound effects on the metabolic processes in the body including insulin resistance, diabetes mellitus, hypothyroidism, metabolic syndrome, glycogen storage disease, and the urea cycle disorder. In total, there are 12 chapters in this book in which the authors have shared their research findings and real-life experiences in managing their patients.