This article reviews Hobday (1998) which was the start of research project of complex products and systems (CoPS) in UK. Since Simon's seminal work, complexity of artifacts has been recognized as important issues for management. Complex artifacts can be seen as a hierarchical system. Recently, a theory of product architecture has given a similar perspective. Hobday defined CoPS as high cost, high value-added products and systems, and are engineering-intensive goods which often require several producers to work together simultaneously. CoPS are often industrial goods customized, one-off or small batch size, over ten years of life cycle, continuing innovation process even after delivery. CoPS research project mainly paid attention to a role of system integrator, and customer or supplier management. Hobday recognized CoPS as a new category to be analyzed by contrast with mass production goods. However, Hobday and following researchers did not operationalize complexity of artifacts. In addition, in CoPS research project, product architecture was treated as given condition. It has not been examined what kind of capability is important for CoPS providers to make architectural dynamics.