Pinch analysis is nowadays a practical tool for designing heat exchanger networks in chemical and process industries. Rules for integrating process units have also been worked out in the last decade or two. Process units can be described as different types of energy unit operations, donors and acceptors. Yet, heat integration alone is not sufficient for process integration. The largest savings are achieved when simultaneously optimizing enthalpy and mass flows energy and material recycling is required to save the natural resources and protect the nature. Mathematical programming is increasingly used to optimize the problems both in continuous and batch operations. Task integration is spreading out: multifunctional units lower the capital investment, thus, the total annual cost. Recent development of the complex integration with examples and reasonable forecast of the future development is presented in the paper.