Photo-induced processes are of tremendous importance in the natural world and across science. Examples include ultrafast process in vision, energy-release by water-splitting in photosynthesis, chemical reactions in the atmosphere, photocatalysis, and technologies such as petahertz electronics, photovoltaics, and light-emitting diodes. Due to the intrinsic complexity of photo-induced processes, they remain the least understood type of physical and chemical processes. Strong and weak laser induced electron and nuclear dynamics on ultrafast time-scales, nonadiabatic dynamics, quantum effects and conical intersections are known to be important, but the full picture is still being unveiled and a cohesive understanding assembled. New experimental techniques, capable of monitoring photo-induced processes with unprecedented temporal and spatial resolution across the entire reaction path, play a key role in this. These developments are driven by the appearance of free-electron lasers, such as the XFEL in Europe, the LCLS (and soon LCLS-II) in the USA, SACLA in Japan, PAL in Korea and Swiss-FEL in Switzerland, new sources of pulsed electrons, table-top based attosecond laser sources, and advanced detection techniques. A large and important contribution is made by advances in theory and computational modelling, in particular in terms of (nonadiabatic) quantum dynamics simulations and theoretical models that improve the interpretation and analysis of experiments.

In this volume the topics covered include:

• Time-resolved Diffraction
• Time-Resolved Ultrafast Spectroscopy
• Strong-Field Physics
• Ultrafast X-ray Science