"Et moi, ..., si javait su comment en revenir, je One service mathematics bas rendered the human race. It bas put common sense back ny serais point all . where it belongs, on the topmost shelf next to lu1esVeme the dusty canister labelled discarded nonsense Eric T. Bell 1be series is divergent; therefore we may be able to do something with it O. Heaviside Mathematics is a tool for thought. A highly necessary tool in a world where both feedback and nonlineari ties abound. Similarly, all kinds of parts of mathematics serve as tools for other parts and for other sci ences. Applying a simple rewriting rule to the quote on the right above one finds such statements as: One ser vice topology has rendered mathematical physics ... ; One service logic has rendered computer science .. .; One service category theory has rendered mathematics .. .. All arguably true. And all statements obtainable this way form part of the raison d etre of this series."