Since 1980, the Design Institute for Physical Property Data(R) has sponsored Project 801 to develop, organize and make available to project sponsors a complete, critically evaluated compilation of thermophysical properties of industrial important chemicals. The database currently contains the properties of over 1700 chemicals and is arguably the best process design database in the world. Project 801 will continue to serve the needs of engineers and scientists in the future as new compounds and data are incorporated into the database and as new capabilities and technologies are implemented. (C) 1998 Elsevier Science B.V. All rights reserved.