The use of the term "advanced" in the title of this book is somewhat ar bitrary and very much relative with respect to time. Many techniques which were considered at the "cutting edge" of ultrastructural methodology just a few years ago are now rou tin ely used in numerous laboratories. One could cite freeze-fracture, cryothin sectioning, or indeed most of the field of scan ning electron microscopy as concrete examples. Thus the use of the term "ad vanced techniques" must be interpreted with regard to the present state of the art, and is useful only in informing the potential reader that this...