This book on carbon fiber research is designed to initiate graduate students into the field and for use by professionals already working in it. The coverage is comprehensive and emphasizes topics of particular interest to physicists and materials scientists. This book is written from the point of view of the basic science underlying the structure and properties of carbon fibers. Emphasis is given to those analytical techniques which have been successfully applied to bulk graphite and are now being applied to the study of carbon fibers. The book specifically considers the preparation, microstructure and defects, electronic structure, lattice, thermal, mechanical, magnetic, electrical and high temperature properties of carbon fibers, together with modifications induced by intercalation and ion implantation, and finishes with a brief discussion of applications. Over 500 references are included which are chosen as much as possible from the recent literature.