Methods in Enzymology, Volume 607: Phosphatases, the latest release in this ongoing series, highlights new advances in the field as detailed by an international board of authors. This latest release includes chapters on Empirical Valence Bond Simulations of the Evolution of Enzyme Function, QM/MM Free Energy and Kinetic Isotope Analysis of Phosphoryl Transfer in Enzymes, the Structural, Mechanism and Evolution of Phosphatases, How to Define Rapid Motions in Pumping Pyrophosphatases, The Evolution of K+-Independence in Pyrophosphatases, the Crystallization of Michaelis, Intermediate and Inhibited Complexes in Phosphatases, and an Investigation of Nucleotide Loading and Effector Binding of K-Ras.