This book was begun after three of the present authors gave a series of in- vited talks on the subject of the structure and properties of carbon filaments. This was at a conference on the subject of optical obscuration, for which submicrometer diameter filaments with high length-to-diameter ratios have potential applications. The audience response to these talks illustrated the need of just one scientific community for a broader knowledge of the struc- ture and properties of these interesting materials. Following the conference it was decided to expand the material presented in the conference...