Over the years the basic principles underlying the practice of neuroanaesthesia have not changed, but introduction of new anaesthetic agents and associated techniques have improved the ability of the neuroanaesthetist to "fine tune" the patients physiological state. This has improved the capacity of the neuroanaesthetist to mitigate the inevitable fluctuations which occur and prevent their ill effects. Further improvement is still desirable and possible. It takes years for the correct plan of usage of new drugs to be formulated for the clinical situation, and their relationships established to new techniques of patient monitoring. Like neurosurgery itself neuroanaesthesia shows no signs of approaching a final definitive state in the forseeable future.