Book excerpt: Nonlinear Optics, Quantum Optics, and Ultrafast Phenomena with X-Rays is an introduction to cutting-edge science that is beginning to emerge on state-of-the-art synchrotron radiation facilities and will come to flourish with the x-ray free-electron lasers currently being planned. It is intended for the use by scientists at synchrotron radiation facilities working with the combination of x-rays and lasers and those preparing for the science at x-ray free-electron lasers. In the past decade synchrotron radiation sources have experienced a tremendous increase in their brilliance and other figures of merit. This progress, driven strongly by the scientific applications, is still going on and may actually be accelerating with the advent of x-ray free-electron lasers. As a result, a confluence of x-ray and laser physics is taking place, due to the increasing importance of laser concepts, such as coherence and nonlinear optics to the x-ray community and the importance of x-ray optics to the laser-generation of ultrashort pulses of x-rays.