It has long been a problem of finding out a proper methodology for dealing with multiscale complex systems, including processes and products. However, it is seemingly impractical to start with the most fundamental structure of the system, and then to extend step by step to obtain its holistic behaviors. The author's idea is to study the system only to set up the ties between some key structure, or dominating-scale structure, and certain holistic performance of the system that interests people, and then to manipulate the found dominating-scale structure to achieve our target. Several cases from the author's laboratory have been quoted for elucidation. Identification of the dominating-scale structure is made on the system individuality base, rather than on some generalized principle. The same viewpoint is suggested when manipulating the dominating-scale structure. (c) 2007 Elsevier Ltd. All rights reserved.