This brief survey will of necessity be a highly personal one. It seemed to me advisable to list only those topics that have been thrown into relief by recent work undertaken by my colleagues, my pupils and myself, and I have not attempted to present these topics in any systematic way. In some instances the requirement is clear: future work will be hamstrung until this or that subject has been fully explored and the results of the research made available in a cheap and readable form. In other cases the projects are more Utopian. All of them, however, have forced their way into recent work of one kind or another so that, whatever their other faults or merits, they are at least up-to-date. I have classified them rather loosely into somewhat sprawling groups, having nevertheless some ground in common.