With the development of lasers that can generate light 11 14 pulses ranging from 10- - 10- sec duration, and capable of 13 peak powers in excess of 10 watts scientists have been able to investigate the interactions of light with matter in a time and power domain not previously possible. These ultrashort laser pulses provide a powerful tool for the study of chemical phenomena at the most fundamental level. Many of the elementary processes of importance in chemistry including energy dissipa tion, molecular motions, structural and chemical changes occur on a very short time scale and thus require special approaches. Th use of ultrashort laser pulses to perturb and to probe systems of interest affords a direct approach to the time reso lution of very rapid chemical phenomena. It was recognition of the impact of these relatively new approaches to chemical phenomena that motivated NATO to sponsor a meeting on the applications of picosecond spectroscopy in chemistry. The primary aim of the NATO workshop was to gain some perspective on the status of the field in terms of present research activities, technological developments and if possible the difficult task of sensing future directions. The way we decided to approach these issues was to gather together the main contributors to the field, fortunately many of whom were able to attend, to present their work and to participate in what turned out to be lively discussions of the field."

The third international conference devoted to picosecond phenomena was held June 16-18, 1982 in Garmisch-Partenkirchen, West Germany. Scientists from widely varying disciplines, physicists, chemists, biologists, and engineers came together to share their common interest in picosecond and subpicosecond processes. The meeting attracted approximately 250 scientists from numerous countries around the globe. More than .100 papers were concerned with the latest advances in the ex- perimental and theoretical understanding of ultrafast phenomena. New dis- coveries in femtosecond and picosecond pulse generation and new results in chemical dynamics, solid-state physics, and nonlinear optics were presented. The quality of the scientific reports, the enthusiasm of the participating scientists, as well as the magnificent surroundings of the Bavarian alps guaranteed a successful and pleasant conference. Numerous people have helped to make the conference a success. Special thanks are due to Carin von Oberkamp for dOing a superb job in implementing the meeting arrangements and to the program committee for the selection and organisation of the scientific presentations. The financial support of the Deutsche Forschungsgemeinschaft and of the Bayerische Staatsministerium fUr Unterricht und Kultur is gratefully ack- nowledged.

With the development of lasers that can generate light 11 14 pulses ranging from 10- - 10- sec duration, and capable of 13 peak powers in excess of 10 watts scientists have been able to investigate the interactions of light with matter in a time and power domain not previously possible. These ultrashort laser pulses provide a powerful tool for the study of chemical phenomena at the most fundamental level. Many of the elementary processes of importance in chemistry including energy dissipa tion, molecular motions, structural and chemical changes occur on a very short time scale and thus require special approaches. Th use of ultrashort laser pulses to perturb and to probe systems of interest affords a direct approach to the time reso lution of very rapid chemical phenomena. It was recognition of the impact of these relatively new approaches to chemical phenomena that motivated NATO to sponsor a meeting on the applications of picosecond spectroscopy in chemistry. The primary aim of the NATO workshop was to gain some perspective on the status of the field in terms of present research activities, technological developments and if possible the difficult task of sensing future directions. The way we decided to approach these issues was to gather together the main contributors to the field, fortunately many of whom were able to attend, to present their work and to participate in what turned out to be lively discussions of the field."

The motivating idea of the first Topical Meeting on Picosecond Phenomena, which took place at Hilton Head Island in 1978, was to bring together scien tists and engineers in a congenial setting who were developing picosecond lasers with those who were applying them to problems in chemistry, physics, electronics, and biology. The field has advanced remarkably in the following six years. This is reflected in the size of the conference which has more than doubled in the past six years and now includes scientists from many countries around the world. As evidenced by the papers in this volume, the appl ication of ultrafast 1 ight pulses continues to grow in new and diverse directions encompassing an increasingly wide range of subject areas. This progress has gone hand-in-hand with the development of new and more precise methods of generating and measuring ultrafast light pulses, which now extend well into the femtosecond time domain. It was this latter advance which was responsible for changing the name of the conference to Ultrafast Phenomena. The 1984 meeting was held at the Monterey Conference Center in Monterey, Cal ifornia from June 11 to 15 under the sponsorship of the Optical Society of America. A total of 320 registered participants, including 65 students, attended the three and one-half day conference. The overall enthusiasm of the participants, the high quality of the research presented, and ambiance of the setting combined to produce a successful and enjoyable conference."

This second edition in paperback provides an up-to-date review of the state of the art in different generation processes for ultrashort laser pulses. Inaddition, extensive applications in a wide range of fields - in physics,engineering, chemistry, and biology - are discussed: Eight chapters dealwith the following topics: -the generation of picosecond and femtosecond laser pulses -nonlinear wave interactions - new investigations in solid-state physics - recent progress in optoelectronics - advances in coherent material excitations - ultrafast vibrational lifetimes and energy redistribution in liquids - new observations of chemical reactions in the liquid state - the primary processes of important biological systems The book is essential reading for scientists and engineers who want to know what is going on in this rapidly advancing field. It should also interest graduate students and others who seek an introduction to laserpulses.