This volume is a kind of celebration of the progress of freeze-fracture electron microscopy in recent years. Many of the authors are leaders of the advancing front. Instead of offering an instruction manual of how to perform new techniques or a review to recover what has happened in the past in respect fields, both which are abundantly available as journal articles and monographs, this volume is a collection of personal testimonies as examples of the power of the new freeze-fracture technology. Since each chapter also centres around specific biological problem, it also serves to illustrate how much the understanding of the problem has been advanced by the new freeze-fracture methodology, which is most cases is developed by the author(s) themselves. A characteristic of frontier development is that many chapters are dealing with controversial subjects. The Inclusion of these subjects in the volume represents the dynamic nature of the subject as viewed by the authors rather than the final verdicts of the subject matter.