Separation processes are basic to the petroleum, chemical, petrochemical, energy, food products and minerals industries. Because of major changes in the economics governing plant design, environmental considerations, political and natural considerations of raw material, a larger effort in the future will be devoted to the selection, design and operation of separation processes. The subject matter of separation processes is very broad and therefore specialization has become the rule. Both the scope and depth of coverage in this handbook is very strong, as is the coverage of fundamentals underlying all separation processes, in the treatment of packed columns and in the vital area of tray efficiency estimation. Because of the diversity of specialization indicated above, an up-dating of information dealing with the technology related to the operations that now constitute separation processing is indicated and this book will fill that need.