Since the publication of the Third Series atlas on heart tumors, there have been several changes in the pathology and classification of these lesions. The current edition updates the status of heart tumors, with emphasis on newer findings, especially molecular advances. In most cases, the authors have followed the classification of the World Health Organization, whose updated volume on tumors of the lung, heart, and mediastinum is forthcoming. Because newer imaging modalities, especially cardiac magnetic resonance imaging and 3-D echocardiography are increasingly utilized in preoperative evaluation of heart tumors, the authors have introduced a chapter devoted exclusively to radiologic diagnosis. In addition, inflammatory myofibroblastic tumor, a less common tumor of heart valves, is covered quite differently from the previous volume, since several reports and series of this childhood tumor have emerged. This atlas has carried over a discussion of lesions that are neither neoplastic nor hamartomatous, such as thrombi and some infections that can mimic tumors, because some of these lesions, especially thrombi, are among the more commonly excised heart masses, and may present diagnostic challenge. This work is a useful source for physicians who wish to find a reference to classify a tumor of the heart, or update their knowledge of these lesions.