Book excerpt: Photo-Excited Processes, Diagnostics and Applications covers the area of photo-excitation and processing of materials by photons from the basic principles and theories to applications, from IR to x-rays, from gas phase to liquid and solid phases. The various chapters give a wide spectral view of this developing field. Twelve leading groups worldwide set down to write this book during the past two years which include the most updated techniques used in their laboratories for investigating photo-excited processes and new applications. This book will be useful to scientists and engineers who have a strong interest in photo-assisted processes development for microelectronics and photonics.