Astrochemistry is a well-established interdisciplinary subject and the methods for describing time-dependent chemistry in static or slowly-changing regions of interstellar space have been well-developed over many years. Existing astrochemical books normally describe the subject in terms of chemistry in static or slowly-varying astronomical situations but the most significant astronomical regions are those in which the physical conditions change on timescales that are comparable to or shorter than chemical timescales. Written by leading experts in this area, this is the first book specifically devoted to the astrochemistry of dynamically evolving astronomical regions. It provides a comprehensive description of this important area of science, stressing in particular the methods that have been developed for specific purposes. It will be of interest to researchers in astrochemistry, including both chemists and physicists and could form the basis of a postgraduate course for research students in chemistry and physics.