The burgeoning interest in biomembranes in recent years has been such that membranology is now virtuMtyasubject in its own right, cutting vertically, as it were, through the strata of conventional disciplines from mathematics and physics, through chemistry, to biology. The very scope of the topic is thus so daunting that it is tempting to treat it only at one stratum of this hierarchy, be it the biophysics of phospholipid bilayers or the biochemistry of interactions at the cell surface. Such an approach is entirely valid, particularly among specialists with common interests. However, this approach does present a distorted perspective to the newcomer to the field, and, more significantly, it fails to stimulate cross fertil ization of ideas among workers at the various disciplinary levels. For example, as in all areas of molecular biology, the clinicians are frequently unaware of the contributions to their problems that might be made by the application of more basic knowledge and techniques. Conversely, biochemists or biophysicists may be ignorant of the existing practical problems to which they might address their expertise.