The chemical processes and utility industries are central issues to modern living standards. The society evolution dictates that chemical processes will need continuous development and the advantages obtained of using process integration techniques consist in process improvement, increased productivity, energy conservation, pollution prevention, and capital and operating costs reductions of chemical plants. Therefore, the aim of this paper is to present in a comprehensive review the development through the years (1975-2008) of the heat integration and heat exchanger network synthesis (HENS) as a technique of process integration. From an impressive amount of studies related to this topic, a selection with the studies representing the turning points and the emerging trends in developing and improving of heat integration and HENS methods was made. The relationships between domains, authors, and journals, related with the field of research, are presented in an easy understanding visual format through the diagrams provided by CiteSpace II software. (C) 2010 Elsevier Ltd. All rights reserved.