Three topics of major interest for neurosurgeons are covered in this volume of the "Advances in Neurosurgery" series. First, neurosurgical standards of diagnosis and treatment are viewed from several points of view, including the legal one. Secondly, the many aspects of aneurysm surgery are dealt with: timing and grading, monitoring during the operation, post-operative vasospasm, Doppler sonography and new research in subarachnoid haemorrhage. The diagnosis and treatment of malignant gliomas are also discussed. There are preliminary reports on interstitial laser-assisted thermal therapy, immunotherapy and radiopharmaceutical substances as well as the standard forms of neurosurgical and radiation treatment.