This work introduces the fundamental background necessary to understand polymer devolatilization. It elucidates the actual mechanisms by which the devolatilization of polymer melts progresses, and discusses virtually every type of devolatilization equipment available. The work also addresses devolatilization in various geometries and types of equipment, describing the use of falling strand, slit, single-screw, co-rotating and counter-rotating twin-screw devolatilization.