This book describes the most fundamental aspects of biophysical chemistry: thermodynamics for molecular biology, calorimetry, noncovalent interactions between atoms and molecules, hydrogen bonds, intramolecular interactions and cooperativity, aqueous solutions, hydration, compressibilities, the hydrophobic interaction, membranes and detergents, ionization and electrostatic interactions, buffers, Hofmeister series, kinetics of biochemical reactions, transition states, free-energy relationships, isotopes and radioactivity, hydrogen exchange, and mass spectrometry. These chapters are taken from the larger volume "The Physical and Chemical Basis of Molecular Biology" (2010, Helvetian Press, www.HelvetianPress.com).