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CNS Metastases: Neurosurgery in the Aged

subgroup. The occurrence of antibodies to JC virus in most normal adults suggests that disease occurs only when a normally harmless viral infection is somehow reactivated. This situation has similarities with some herpes virus and retrovirus infections, and viral reactivation is currently a crucial question. This book is divided into three sections concerning the virology, epidemiology, and neurological diseases associated with JC and BK viruses. Although each section contains much recent and specialised information there are several chapters giving overviews of various areas. Consequently this book avoids being simply a collection of papers, but stands on its own as an excellent account of current thinking on PML. It should be of interest to graduate students and research workers in many fields, including molecular biology, immunology, virology and neurology. One area of particular interest is the rapid progress being made at the molecular genetic level in identifying possible regulatory sequences in the genome, and the analysis of sequence variation in vivo and in vitro. Another important area is analysis of the oligodendrocyte lesions which are characteristic of PML by the use of antibodies to defined myelin proteins. In view of the possible connection between viral infections and multiple sclerosis and Guillain-Barre Syndrome, it is especially interesting to study a situation where demyelinating virus really is at work.