Book excerpt: Advances in the development of x-ray lasers and other sources of intense x-ray radiation are discussed. Topics include transient x-ray lasers, capillary discharge x-ray lasers, optical field ionization x-ray lasers, x-ray free electron lasers, high-order harmonic sources, characterization of x-ray lasers and x-ray optics, as well as applications of x-ray lasers including x-ray interferometry.