This book is a collection of papers derived from a conference on membranes held at the Columbus Laboratories of Battelle Memorial Institute in Columbus, Ohio, on October 20 and 21,1969. When a decision is made to sponsor a membrane conference, the problem immediately arises as to what aspect of the technology needs to be emphasized. There were several alternatives from which to choose. The Office of Saline Water, for example, has been sup­ porting for many years a tremendous volume of research on the desalination of sea and brackish water. In fact, were it not for this effort, the conference which resulted in this book could probably not have been held. Regardless, one could not easily choose to hold a conference on water desalting because the subject is adequately covered in the literature, and yearly conferences are sponsored by the funding agency. Other government agencies, specifically The National Heart and Lung Institutes and The National Institute of Arthritis and Metabolic Diseases, have supported a sizable number of research programs involving the use of membranes for biomedical devices useful in blood oxygenation and kidney augmentation or replacement. Again, these groups have their own outlets for disseminating research results. Still other choices existed among such areas as permeation processes for petroleum separations, advanced or novel membrane process concepts, or characterization of membranes - morphology, permeation properties, etc. , - or biological membranes. None of these areas seemed to provide just the right technological emphasis.