The tissue culture approach to the study of membrane properties of excitable cells has progressed beyond the technical problems of culture methodology. Recent developments have fostered substantive contributions in research con- cerned with the physiology, pharmacology, and biophysics of cell membranes in tissue culture. The scope of this volume is related to the application of tissue culture methodology to developmental processes and cellular mechanisms of electrical and chemical excitability. The major emphasis will be on the body of new biological information made available by the analytic possibilities inherent in the tissue culture systems. Naturally occurring preparations of excitable cells are frequently of suf- ficient morphological complexity to compromise the analysis of the data obtained from them. Some of the limitations associated with dissected prepa- rations have to do with the direct visualization of and access to the cell(s) in question and maintenance of steady-state conditions for prolonged periods of time. Since preparations in tissue culture can circumvent these problems, it is feasible to analyze the properties of identifiable cells, grown either singly or in prescribed geometries, as well as to follow the development of cellular inter- actions. A crucial consideration in the use of cultured preparations is that they must faithfully capture the phenomenon of interest to the investigator. This and other potential limitations on the methodology are of necessary concern in the present volume.