'Et moi, .. Of si j'avail su comment en revenir. je One selVice mathematics has rendered the n'y semis point alll!.' human race. It has put common sense back Jules Verne when: it belongs, on the topmon shelf next to the dusty canister labelled 'discarded nonsense'. The series is divergent; therefore we may be Eric T. Bell able to do something with iL 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.