Based on the authors' experimental work over the last 25 years, this self-contained book presents basic concepts, state-of-the-art applications, and future trends in optical, atomic, and molecular physics. It gives a wide-ranging, balanced overview of the areas revolutionized by optical frequency comb synthesizers based on femtosecond mode-locke "? [in] this handbook ? the story and the complexity of the variety of methods for improving optical frequency metrology unfold, in particular, the successive improvements of the performance of devices based upon lasers. ? a pleasure to read."-Contemporary Physics, 2014"This is a beautiful and monumental work ? easy to read thanks to its clear and concise style. ? a must-read for anybody working in laser research and industry, and will be particularly helpful for Ph.D. students."-Mircea Dragoman, Optics & Photonics News, January 2014"The authors have made a considerable effort to make this book useful and interesting to different kinds of readers: they provide a detailed treatment of the basic concepts of time and frequency measurements, carefully describe different kinds of lasers and some of the most advanced laser-based measurement techniques, and finally present the latest developments in the field, with a hint to the possible future trends in applications and fundamental science.Being among the many important actors in this long story, the authors of this book are privileged witnesses of the evolution of time and frequency measurements, and can provide an informed and wide vision of this developing field from many different viewpoints."-From the Foreword by Nobel Laureate Professor Theodor W. Hänsch, Ludwig-Maximilians-Universität München