This book presents what are often viewed as the more difficult con-cepts in an introductory biochemistry course and describes them inenough detail and in simple enough language to make them understand-able. We surveyed first- and second-year medical students at a nationalstudent meeting asking them to list, in order, the parts of biochemistrythey found most difficult to understand. The winner (or loser), by far, wasintegration of metabolism. Metabolic control, pH, and enzyme kineticsran closely behind, with notable mention given to molecular biology andproteins..