non-technical fashion and are accessible to a large readership of scientists and also laymen interested in the scientific per­ spectives and logical foundations of the machine concept that has been so influential in western thinking. The idea of the book has its origin in a workshop held at the Sci­ entific Station in Abisko, Sweden, in May 1990, where several of the present authors participated. The meeting was organized and spon­ sored by the Swedish Council for Planning and Coordination of Re­ search (FRN). Since 1983, the FRN has actively promoted a series of such annual events at Abisko, all of which have been devoted to the exploration of various aspects of complex systems and their evolution.