-Et moi, ..., Ii javait so comment en revenir. je One serviee mathematics has rendered the n y serais point all . human nee. It hal put rommon sense back Jules Verne whme it belongs, on the topmost shelf next to the dusty canister labelled discarded nonsense. The series il divergent; therefore we may be EricT. Bell able to do scmething 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 detre of this series.