In the 1980's sonochemistry was considered to be a rather restricted branch of chemistry mainly involving the ways in which ultrasound could improve synthetic procedures, predominantly in heterogeneous systems and particularly for organometallic reactions. This volume traces the evolution of sonochemistry from a century ago when the effects of acoustic cavitation were first reported almost as a scientific curiosity, through the 1980's to the present. It describes the ways in which scientific interest grew rapidly during the 1990's with the formation of the European Society of Sonochemistry in 1990 and the launch of a new journal Ultrasonics Sonochemistry in 1994. It also includes two chapters relating to the evolution of the subject as seen through the particular experiences of the authors Tim Mason and Mircea Vinatoru, both pioneers of sonochemistry. One chapter is devoted to the ultrasonically assisted extraction (UAE) of chemicals from plant material. This also illustrates the different ways in which sonochemical technologies can be applied in both batch and flow systems leading