Thymic carcinomas and thymomas are neoplasms of the epithelial cells of the thymus. Extensive study of the histopathology of these tumors has provided insight into the clinical behavior of various pathological subtypes. Establishment of a uniform staging system has facilitated the prospective study of thymic tumors, and it has helped to provide the necessary framework for international cooperation in the study of these diseases. This review explains the pathological nomenclature used in the classification of these tumors, examines the prospective clinical trials that have been completed to date, and discusses the interesting paraneoplastic phenomena associated with thymomas.