Every year dozens of physicians-in-training face, for the first time, the responsibil ity of examining and diagnosing central nervous system tumors or biopsies of the central nervous system, the peripheral nerves or muscles, whose surgical resection has been decided on both as a form of treatment (in the case of tumors) and as means to confirm a presumptive diagnosis. The selection of the most appropriate form of post surgical treatment for most tumors is predicated on the precise identification of the tumor cells. The evaluation of the specimen, by a pathologist, will not only determine...