A hydrate state-of-the-art is given for fundamental measurements and modeling of phase equilibria and kinetics, via a 204 paper summary of the triennial International Hydrate Conference in May 2002. Emphasis is given to new measurement techniques with their application in the next generation of hydrate modeling. Future challenges are presented. With this Phase Equilibria Plenary Lecture in the 17th International Conference on Chemical Thermodynamics, goes my appreciation for both the honor, and the motivation to attempt a state-of-the-art summary. All too frequently such summaries take on a personal perspective that omit important developments, perhaps because they were not developed by the writer, and were therefore less familiar. Yet currently we are two months after the fourth triennial International Conferences on Gas Hydrates (Yokohama, Japan, 19-23 May 2002). That conference was blessed with a chairman who provided two volumes (1062 pages) written by 500 (even!) authors. A CD of conference papers is available at nominal cost through the ICGH-4 Secretariat ([email protected]). The challenge of this invited manuscript is to provide a pure and applied phase equilibria summary of the above conference, supplemented by a few other references, in an overview of the hydrate community's current direction. The conference provides a technical snapshot of hydrate research over the world, making it possible to weave a few current threads into the hydrate fabric in space and time. Emerging images provide some clues to the future. To supplement this view the reader may wish to turn to the other reviews [1-6] on pure and applied phase equilibria of hydrates. (C) 2003 Elsevier Science Ltd. All rights reserved.