Just after the International Quantum Electronics Conference, which took place in Tokyo, July 18-21, 1988, a symposium on "Nonlinear Optics of Org~ics and Semiconductors" was held on the Hongo campus of the University of Tokyo on July 25 and 26, 1988. Recently, nonlinear optical materials have started to attract the attention of many scientists, not only in the field of quantum electronics but also in organic chemistry, and solid-state physics, especially semiconductor physics. Therefore this area of investigation is really interdisciplinary and necessitates understanding from different viewpoints for continuous growth of the research activity in the field. This book contains many papers written by scientists active in the field of nonlinear optics of organic materials and semiconductors. The first two parts of the book discuss mainly the basic physics of nonlinear optics of semiconduc­ tors, including bulk and quantum well structure semiconductors. The papers in Parts ill-VIII concern mainly organic materials. They include the calculation of molecular polarizability, synthesis, the measurement of optical nonlinearity and characterization. The final part is on potential device applications. The symposium was organized in collaboration with Prof. Shinsuke Umegaki of Tokyo Technical Institute, and Dr. Hachiro Nakanishi of the Research Institute of Polymers and Textiles. Preparations for the conference were made with the help of Dr. Masayuki Yoshizawa, Miss Nanae Indou, Mrs. Yoko Sasaki and graduate students (Mrs. T. Hattori, M. Terauchi, K. Ichimura, A. Terasaki, K.