Professor Kivshar has established himself as a world leader in nonlinear optics, a subject of central importance to the development of photonics. For this work he received in 1995 the International Pnevmatikos award for research in nonlinear phenomena. He has developed the theory of self-trapped beams (spatial solitons) for alloptical nonlinear switching devices and also the first nonlinear theory of stability of multi-parameter nonlinear solitary waves. This has been applied by others to many different physical problems. He has worked closely with several experimental groups in verifying many of his predictions.