Photochemical reactions have tremendous scientific importance, ranging from photosynthesis to atmospheric reactions, and technologies such as sensors or displays. Due to the intrinsic complexity of photochemical reactions, they remain the least understood type of chemical process. Nonadiabatic dynamics, ultrafast time-scales, quantum effects and conical intersections are known to be important, but a detailed comprehension remains elusive. However, new experimental techniques capable of monitoring photochemical processes in unprecedented detail are appearing. This includes the development of intense-laser techniques, the construction of free-electron lasers such as the XFEL in Europe and the LCLS in the USA, new sources of pulsed electrons, advanced detection techniques, and important advances in theoretical modelling of quantum dynamics. Many of these techniques are developed by research communities not traditionally concerned with photochemistry, but provide an opportunity to shed new light on photochemical dynamics.