I am grateful to
- Gordon Finlayson from York University for giving me the opportunity to give these lectures and teach two seminars with him, for his hospitality during the week when we did so, and for many inspiring discussions during that week;
- the 3rd year PEP students who all attended the four lectures as extra lectures during week 1 of the term and and whose contributions in the seminar sessions I liked a lot;
- Thomas Baldwin from York University who initiated the SOCRATES exchange between our two departments;
- the European Community (i.e. its tax payers) for making the lectures possible by paying for my ticket.
- Nicholas White (Salt Lake City), Burkhard Hafemann (Münster) and my wife Mechthild Strobach for very valuable and encourageing commentaries and criticism.
N.St. Nov 99