Electronic Journal of Differential Equations, Vol. 2000(2000), No. 48, pp. 1-26. Title: Models for phase separation and their mathematics Author: Paul C. Fife (Univ. of Utah, Salt Lake City, UT, USA) Abstract: The gradient flow approach to the Cahn-Hilliard and phase field models is developed, and some basic mathematical properties of the models, especially phase separation phenomena, are reviewed. Submitted February 10, 2000. Published June 22, 2000. Math Subject Classifications: 35K55, 80M35, 74A25. Key Words: Cahn-Hilliard equation; phase-field equations; phase separation; gradient flows.