Clinical studies during the past 10 years have shown that PET is more sensitive than CT and MRI for the detection of many tumors. In many cases, however, for example in head and neck tumors, combination with radiological procedures is necessary. It may be speculated that PET should be the first study in a malignant tumor when metastatic spread is suspected. MRI and CT may then be restricted to those body areas which evince sites of increased glucose metabolism. Thus, a combination of metabolic and morphologic procedures will enhance tumor detection and change the therapeutic strategy. In this light, an atlas including PET, CT, MRI, and histology data seems desirable to combine metabolic and morphologic imaging. This book presents an overview of the available data which should be of great interest not only for specialists in radiology and nuclear medicine, but also for oncologists.