Introduction

All kinds of choices have had to be made – especially about what to exclude! – either simply for reasons of space, or in order to try not to overburden readers who may still be at an elementary level in their knowledge of the language. (The dangers of over-simplification are of course ever-present, and the author is all too aware that he may have succumbed to these at times – he hopes not too often.)

Efforts have been made to separate the basic, core elements from those which are less central and vital.