Active suspensions: some background

The paper is intended to serve as an introduction to a set of three specially selected papers on suspension control systems. In this spirit, the authors briefly review the area of active suspensions and provide some introductory background, history and facts that will enable the reader to place the selected papers in context. Although this is not a comprehensive review, the authors have elected to give references and a bibliography to draw attention to articles and sources which are often not mentioned in scientific surveys of active suspension