In recent years there have been many important advances in knowledge concerning the mechanisms of chemical synaptic transmission, the identification of the neurotransmitters and the mechanisms by which drugs act on the nervous system. These advances have necessitated a change in approach to the teaching of the pharmacology of the nervous system to undergraduate science and preclinical medical students from a basically therapeutic orientation to one which is more mechanistically minded. In giving such courses to students in Cambridge, the author has become painfully aware of the need for an undergraduate text which could fulfil the needs of students in this respect. There are of course many excellent textbooks of therapeutics available but few of them attempt to cope in detail with mechanisms of drug action, especially on the central nervous system, except from rather specialised viewpoints. It was therefore considered to be unnecessary to discuss therapeutic applications in detail in this book, although an attempt has been made to give a fairly balanced account of the physiological basis, applications and mechanisms of action of each class of drugs, within the limitations imposed by the objective of producing a concise account of drug actions.

Advances are occurring at such a rate that some of the concepts which are current today may be superseded tomorrow: this is probably true for any subject that is ‘alive’ and progressing. However, this does create problems in deciding what to omit and what to include.