Published appraisals of real-time three-dimensional transesophageal echocardiography (TEE) is a breakthrough technology feasible in most patients, permitting faster image acquisition, and delivering superior images of certain cardiac structures than can be obtained with either real-time transthoracic echocardiography (TTE) or reconstructed 3D TEE imaging technology. The technology is used predominantly for the preoperative assessment of the mitral valve and, going forward, for the guidance of percutaneous procedures, such as interatrial septal occluders, occlusion of the left atrial appendage, and reduction of mitral regurgitation, using either clips or annuloplasty devices. This atlas is intended as the first book to provide a comprehensive description of normal anatomy of the internal structures of the heart (natives valves, interatrial septum, left atrial appendage, left atrium etc..) as seen by this revolutionary ultrasound technique. In the section I, after a brief introduction of the physical principles, normal TEE cardiac structures will be described and compared side-by-side with the corresponding anatomical specimens focusing on the fundamental as well as the details of the cardiac structures. Anatomic specimens will be provided by Prof Ho head of Cardiac Morphology National Heart and lung Institute Imperial College in London. This will provide a fine understanding of the actual anatomy and relationships between structures that were not previously observed with either real-time transthoracic echocardiography (TTE) or reconstructed 3D TEE imaging technology.Section II will focus on a large number of challenging cardiac pathology cases observed in clinical settings and based of the combined experience of five outstanding Institution in Europe and United States. Each case is accompanied by a brief presentation and discussion of the value of the imaging modality to effective diagnosis. The format will use a question and answer technique to reinforce the teaching value of the Atlas.