There is a growing need for a comprehensive reference book of this type due to knowledge explosion and curriculum modularization at all levels and in all areas of Biochemistry. The "Essential Concepts in Biochemistry" is intended to bridge this gap. The authors draw on their extensive and intensive teaching and research experience to provide reference book for students taking Biochemistry at both under graduate and graduate levels as well as both researchers in life Sciences and teachers of Biochemistry. This book contains three parts. Part I deals with Chemistry, Classification and properties of Bio-molecules. Part II includes Metabolism of Various Bio-molecules and Part III covers special topics such as rumen Metabolism, Photosynthesis, Cellular Communications and biological membranes. The book contains 19 chapters covering Carbohydrates, Lipids, Amino acids and Proteins, Nucleic acids including their metabolisms and regulations. At the end of metabolisms clinical importance or metabolic disorders also included. The book is written in a simple and lucid way with several examples and illustrations.We express our deep gratitude to all our colleagues at Jigjiga University.