'Et moi, ..., si j'avait su comment. One service mathematics has ren- en revenir, je n'y serais point alle'. dered the human race. It has put common sense back where it be- Jules Verne longs, on the topmost shelf next to the dusty canister labelIed 'discard- The series is divergent; therefore we ed nonsense'. may be able to do something with Eric T. Bell it. O. Heaviside Mathematics is a tool for thought. A highly necessary tool in a world where both feedback and nonlinearities abound. Similarly, all kinds of parts of mathematics serve as tools for other parts and for other sciences. Applying a simple rewriting rule to the quote on the right above one finds such statements as: 'One service topology has rendered mathema- tical physics ...'; 'One service logic has rendered computer science ...'; 'One service category theory has rendered mathematics ...'. All ar- guably true. Alld all statements obtainable this way form part of the raison d 'etre of this serics.