Since the publication of the first edition 15 years ago, the subject of liquid crystals has grown enormously to become a fascinating interdisciplinary field of study. A variety of new thermotropic phases have been discovered, including over a dozen different smectic modifications, discotics, biaxial nematics, etc., which have opened up a veritable treasure-house for the theoretical condensed matter physicist. On the technological side, the advances have been no less spectacular: portable computers and hand-held TV sets using liquid crystal display devices are being sold in large numbers, and high-definition LCD-TV would seem to be just round the corner. The aim of the present edition is to bring the coverage up to date. The chapters dealing with the classical nematic, cholesteric and smectic types of liquid crystals have been revised substantially and a new chapter has been included on discotics. However, mainly for reasons of space, special topics like the applications of magnetic resonance techniques, non-linear optical properties, etc., have not been discussed here as these have been comprehensively reviewed elsewhere.

It is my privilege to express my thanks to my young colleagues who kept me alive to the subject: in particular to V. N. Raja, S. Krishna Prasad, D. S. Shankar Rao, S. M. Khened and Geetha Nair for their invaluable help throughout the preparation of this book, and to Sriram Ramaswamy and U. D. Kini for their advice on certain theoretical points. I am indebted to the Council of Scientific and Industrial Research, New Delhi, for a Bhatnagar Fellowship which made it easier for me to undertake this task.