At a recent meeting to discuss the domains of cell biology, I put forth a case for the extracellular matrix, even though my argument ran the risk of falling on deaf ears. After all, the matrix is EXTRAcellular, outside the cells. In this book, however, the authors make a compelling case for the relevance of the matrix to cellular concerns. Not only are numerous cell types, including many epithelia, quite caught up in the business of manufacturing matrix components, but also most of them contain matrix molecules in exoskeletons that are attached to the plasmalemma and that organize or otherwise influence the affairs of the cyto plasm. The idea of this book is to present the extracellular matrix to cell biolo gists of all levels. The authors are active and busy investigators, recognized experts in their fields, but all were enthusiastic about the prospect of writing for this audience. The chapters are not "review" articles in the usual sense, nor are they rehashes of symposium talks; they were written specifically for this book and they present the "state of the art" in engaging style, with ample references to more technical or historical reviews. The book is rich in electron micro graphs and diagrams and for many of the latter, as well as for the design of the cover, we are indebted to Sylvia J. Keene, medical illustrator for the Department of Anatomy at Harvard Medical Scrool. We also owe special thanks to Susan G.