Process-Network Synthesis or PNS in short formally defined by Friedler and Fan in 1991 is the constructive procedure of building up complex processes or networks from elementary building blocks in order to achieve overall targets by the help of external and internal resources. Advanced algorithmic methodologies and computational tools developed in the last quarter of century could overcome the combinatorial explosion caused by the large number of alternative combinations of process elements having the potential to achieve the desired overall target facing industrial size problems. Moreover, aiming at finding the global optimum multiple component problems of the process-synthesis traditionally examined sequentially become solvable in integrated way, including reaction path synthesis, separation-network synthesis, heat integration, control design, and scheduling. The presentation aims at reviewing the related methods and software. Latest developments and future challenges are to be highlighted as well.