Until recently, the subject of chemical process synthesis was largely ignored in the chemical engineering literature despite its importance in chemical engineering practice. However since 1968, attention to the subject has greatly increased and important progress has been made. This review article critically surveys the readily accessible literature in chemical process synthesis from two points of view: theory and applications. It is concluded that a number of effective synthesis tools are now available for application in industrial chemical process design. However, much more remains to be done, particularly with regard to the development of synthesis procedures which can lead to novel processing system structures.