One service mathematics has rendered the Et moil "" 1 .i favait su comment en revenir. je ny scrais point all .- human race. It has put oommon sense back Jules Verne when: it belongs, on the topmost shelf next to the dusty canister labelled discarded nonsense. The series is divergent; therefore we may be EricT.Bell 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 detre of this series.