The work on which the content of this book is centred took<br >place over more than a decade. It started， in the middle fifties，<br >with the construction of adaptive training machines， with super-<br >flcla!ly disconnected studies of chemical computing systems，<br >ai~d. towards 1960， with experiments on machine-monitored<br >small gToup inter-action. Since that period an underlying theory<br >has emerged from a gaggle of prescient concepts. It owes a great<br >deal of its present shape to the ideation and criticism of friends<br >and colleagues， only some of whom can be mentioned directly~<br > First of all， it is noteworthy that parallel work has gone on in<br >two places; my own laboratory at System Research Ltzl and in<br >tteinz Von Foerster s Biological Computer laboratory， at the<br >University of Illinois. Both endeavours were encouraged by<br >Warren McCulloch; the reader will detect the influence of his<br >ideas and guidance appearing repeatedly throughout the discus-<br >sion. Apart from this， the parNlel development was not specially<br >contrived and it was sustained by irregular personal liason.<br >t]ence， it is gTatifying to find that recent publications from the<br >Biological Computer Laboratory image our own conclusions，<br >differing， chiefly， in the notation employed and the area of<br >application. People familiar with the field will probably find the<br >threads of mutualism quite obvious; for the benefit of others， a<br >few of these threads are picked out. For example， Loefgren<br >worked with Von Foerster whilst refining the formalism on<br >which the currently-used type of abstract reproductive and<br >evolutionary process is founded; Matturana (whose theory of<br >autopoietic systems is the analogue， in a biologist s mind， for<br >certain stable cognitive organisations in the present theory)<br >worked there as well; Matturana s theory is to appear m a<br >subsequent monograph in this series. Both Ashby， the system<br >theorist， and Gunther， the philosopher， taught and researched<br >with Von Foerster; much of the present theory hinges upon<br >their ideas.<br > On home ground， the theory， and the experiments as well，<br >owe a great deal to two colleagues of long standing: Brian Lewis<br >and Bernard Scott. Prof. Lewis m~d I shared a common interest<br >IX<br >