This volume is the last in the series comprising "Water-A Comprehensive Treatise. " It was originally planned to combine aqueous solutions of macro­ molecules and disperse systems in one volume, but largely because of the extensive coverage required by recent developments in aqueous solutions of proteins and synthetic polymers I decided to separate topics dealing with water in disperse systems. The systems treated in the present volume are of a complex nature so that the theoretical frameworks established earlier in Volume 1 and utilized in Volumes 2 and 3 cannot at the present time be applied. On the other hand the systems discussed in Volumes 4 and 5 in particular, border on the many biological and technological areas where important attributes are related to the common factor-water. Included among such diverse problem areas are food processing and preservation, cryopreservation, paper and textile finishing, membrane processes, hemodynamics, etc. It is to be hoped that in days to come some of the results and principles discussed in these five volumes can be applied to improve our understanding of the complex in­ teractions in medically and industrially important spheres of scientific ac­ tivity. An age seems to have passed since the concept of creating this treatise was first discussed, and since work began on Volume 1, much has happened in the science of Water; some of the recent developments were highlighted at this year's Gordon Research Conference in Plymouth, N. H.