The First International School on Electromagnetic Fields and Biomembranes took place in Pleven, Bulgaria on 6-12 October 1986. It was designed as an advanced course through a collaboration of the Biological Faculty of Sofia University and the Council of the Bioelectrochemical Society. In an advanced course the lecturers are specialized in particular areas, and the students are usually specialists in related areas. We have captured the expertise of both groups of participants in this volume. The longer papers prepared by the lecturers are joined with the shorter papers based on the posters presented by the students to provide a summary of the school as well as an indication of current research directions in the field. The course was designed to provide the latest information about biomembrane structure and function, covering the properties of both the lipid matrix and the recently characterized proteins that function as specialized channels and receptors. Real membranes and various models were covered, with an emphasis on understanding their mechanisms of interaction with various exogeus stimuli (e.g., electric, magnetic, light, etc.). Several practical applications of this information (e.g., electroporation, electro-fusion) were also presented with indications of the possibilities for new developments in biotechlogy. The mixture of basic science with practical applications, together with the int rmingling of lecturers and students from many different countries produced a stimulating atmosphere and effective teaching. We hope that this volume will transmit some of this atmosphere.