Kenneth A. Johnson is The Roger Williams Centennial Professor of Biochemistry at The University of Texas at Austin, and President and founder of KinTek Corporation, Austin, Texas USA. He previously served as the Paul Berg Professor of Biochemistry at The Pennsylvania State University. He is the author of over 200 publications on enzyme reaction mechanisms, is recipient of the Pfizer Award in Enzyme Chemistry, and a Fellow of the Biophysical Society and the American Association for the Advancement of Science. In this text, Dr. Johnson shares his knowledge gained in decades of research on enzyme reaction mechanisms.