The initial focii for process systems engineering were in process control and design. While initially confined to regulatory control of units and process trains, the former area has expanded to encompass the additional decision layers of the operational hierarchy from process monitoring through real time optimization and most recently supply chain and even enterprise-wide operational management. In this paper we will review this evolution both in terms of the technical developments and the supporting conferences, meetings and publications which served to bring together the sector of the pse community with interests and needs in process operations.