This is the annual progress report for the Grant DE-FG03-96ER45572. This research is on the entropy of materials, particularly alloy phases. It is an experimental effort utilizing inelastic neutron scattering facilities at two DOE facilities: Oak Ridge National Laboratory (HFIR) and Argonne National Laboratory (IPNS), and the NIST Center for Neutron Research. It includes an overview of completed research in 2000, a list of publications, and personnel supported under this grant.