In writing this book, I have attempted to provide information about the relative value of particular investigations in various neurological disorders. The book is divided into sections dealing with the methods of investigation, the investigation of particular symptoms, the investigation of specific neurological conditions and neurological emergencies. Finally, the assessment of certain disorders suggesting a particular anatomical localization, for example isolated optic atro- phy, is considered. Following an appraisal of the literature, each section ends with a recommendation regarding appropriate investigation. In some in- stances this is supported by an algorithm. Specific recommendations have been attempted despite the risk of producing over-dogmatic criteria for patient management. A small amount of illustrative material is included. I am grateful to colleagues at Charing Cross Hospital who have provided some of the illustrations. Figs 1. 4, 2. 1 and 10. 2 are reproduced from Atlas of Clinical Neurology, by G. D. Perkin eta/. , Gower Medical Publishing, 1986, courtesy of the publishers. Fig. 3, in Chapter 4, is reproduced from Brain, vol. 2 104, 753-78, 1981, courtesy of the editor and Dr. R. S. J. Frackowiak. Fig. 6, in the same chapter, is reproduced from Fig. 62 in the Atlas of Positron Emission Tomography, edited by E-D. Heiss et al. , Springer-Verlag, 1985, courtesy of the publishers and Dr. J. C. Maziotta. Fig. 3 in Chapter 6 is reproduced from Fig.