These proceedings comprise a selection of invited and contributed papers presented at the 15th International Conference on X-Ray Lasers (ICXRL 2016), held at the Nara Kasugano International Forum, Japan, from May 22 to 27, 2016. This conference was part of an ongoing series dedicated to recent developments in the science and technology of x-ray lasers and other coherent x-ray sources with additional focus on supporting technologies, instrumentation and applications. The book showcases recent advances in the generation of intense, coherent x-rays, the development of practical devices and their applications across a wide variety of fields. It also discusses emerging topics such as plasma-based x-ray lasers, 4th generation accelerator-based sources and higher harmonic generations, as well as other x-ray generation schemes.

S.V. Bulanov is currently a Distinguished Research Fellow at the National Institutes for Quantum and Radiological Science and Technology (QST). He graduated from the Moscow Institute of Physics and Technology, USSR, and earned his Ph.D. in theoretical physics and astrophysics in 1974. He worked at the P.N. Lebedev Physical Institute of the Academy of Sciences of the USSR and then at the Russian Academy of Sciences' General Physics Institute in Moscow, where in 1990 he was awarded his Dr.Sci. degree and where he is now a scientist in chief. He was a professor of physics and mathematics at the Moscow Institute of Physics and Technology, Russia. He joined the Japan Atomic Energy Research Institute (JAERI, then JAEA and QST) in 2002. His fields of study include the physics of nonlinear processes and charged particle acceleration in space and laboratory plasmas. He has received several notable prizes including the USSR for Science and Technology's State Prize and the European Physical Society's Hannes Alfven Prize. S. V. Bulanov has published 2 monographs and 600 papers.  Yoshiaki Kato is currently president of The Graduate School for the Creation of New Photonics Industries (GPI) and president of The Laser Society of Japan. He graduated from the University of Tokyo and earned his Ph.D. in 1970. From 1975, he was engaged in high-power laser, laser fusion, x-ray laser, and laser electron acceleration research at the Institute of Laser Engineering, Osaka University. He co-chaired the 6th International Conference on X-Ray Lasers (ICXRL) in Kyoto in 1998 with H. Daido and H. Takuma. From 1998 to 2007, he was at the JAERI/JAEA Kansai Photon Science Institute (KPSI). He joined the GPI in 2007. He promoted high field science as chair of the OECD Global Science Forum Working Group on Compact, High-Intensity Short-Pulse Lasers from 2000 to 2004, leading to the establishment of IUPAP ICUIL (The International Union of Pure and Applied Physics, International Committee on Ultra-Intense Lasers) and the Asian Intense Laser Network, both in 2004. He has received several awards, including the American Physical Society's (APS) Award for Excellence in Plasma Physics Research. Y. Kato has published 350 papers. Hiroyuki Daido is currently the director of the Naraha Remote Technology Development Center, Japan Atomic Energy Agency (JAEA). He earned his doctorate degree from Osaka University in 1981. From 1991 to 2000 he worked at the Institute of Laser Engineering (ILE) Osaka University where he focused on CO2 laser-driven inertial fusion, soft x-ray lasers and incoherent soft x-ray sources and their applications. He moved to the Kansai Photon Science Institute (KPSI) of JAEA in 2000 where his work involves ultra-high intensity physics, and the development of ion sources and their applications. From 2009 to the present, he has been engaged in the study of laser technology for decommissioning nuclear facilities as well as maintaining social infrastructures. T. Kawachi is the director of the Kansai Photon Science Institute (KPSI) National Institutes for Quantum and Radiological Science and Technology (QST). He earned his Ph.D. from the Kyoto University in 1995. He started his career as a researcher at The Institute of Physical and Chemical Research (RIKEN) in 1995. He joined the Japan Atomic Energy Research Institute (JAERI) in 1998, where he took part in the table-top x-ray laser research project. He has achieved several remarkable results on laser-based plasma x-ray. Recently, he won the TAIZAN Award together with Dr. H. Daido from the Institute of Laser Technology.