This textbook is designed to help the busy radiation oncologist to accurately and confidently delineate tumor volumes for conformal radiation therapy (including IMRT). The book provides an atlas of clinical target volumes (CTVs) for commonly encountered cancers, with each chapter illustrating CTV delineation on a slice-by-slice basis, on planning CT images. Common anatomic variants for each tumor are represented in individual illustrations, with annotations highlighting differences in coverage. The anatomy of each site and patterns of lymphatic drainage are discussed, and their influence on the design of CTVs is explained in detail. Utilization of other imaging modalities, including MRI, to delineate volumes is highlighted. Key details of simulation and planning are briefly reviewed. Although the emphasis is on target volume delineation for conformal techniques, information is also provided on conventional radiation field setup and design when IMRT is not suitable.