Book excerpt: This book summarizes the current status of research on bilayer lipid membranes (planar lipid bilayers and spherical liposomes). In addition to describing the properties of lipid bilayers and examining biomembrane phenomena, the book has two other objectives. The first is to present practical methods for the formation and study of lipid bilayers with either aqueous or metal-lipid bilayer interfaces. The second aim is to treat planar lipid bilayers as a new type of interfacial adsorption phenomena. The first nine chapters cover properties of biomembranes, basic principles of membrane biophysics, transport, electrochemistry, physiology, bioenergetics, and photobiology. Chapter 10 presents the following topics: lipid bilayers in medicine, supported lipid bilayers as sensors, a short discussion of liposomes, and solar energy transduction via semiconductor septum photovoltaic cells based on natural photosynthesis.