Book excerpt: This book provides up-to-date guidance on the use of FDG PET to assess the biological activity and treatment response of a wide range of malignancies, including, for example, lung cancer, breast cancer, head and neck cancer, gastrointestinal cancer, and malignant lymphoma. In the era of precision medicine, numerous new anticancer agents, such as molecular targeted agents and immune checkpoint inhibitors, have been developed to improve outcomes in cancer patients. FDG PET plays a key role in evaluating the effects of these novel treatments because it can detect changes in the metabolic activity of tumors before any reduction in their size is visible on other imaging modalities. Accordingly, FDG PET is of prognostic as well as diagnostic value, and allows prompt changes in patient management. The book is written by expert clinicians from Japan, where the universal public health insurance system ensures that FDG PET is widely used in routine oncological practice and cancer screening. It represents an unrivaled and comprehensive resource that will be of value for all healthcare professionals in the field of clinical oncology.