I. Introduction.- II. Cell Membrane-Associated Antigens.- 1. Immunity Against Cell Membrane-Associated Antigens.- III. Antigenic Changes During Embryonic Development.- IV. Tumor-Specific Antigens.- V. Carcinoembryonic Antigens.- 1. Cell-Surface CEA.- 2. Alpha Fetoprotein.- 3. Carcinoembryonic Antigens of the Digestive Tract.- 4. As Yet Undefined Carcinoembryonic Antigens.- VI. Properties of Carcinoembryonic Antigens.- 1. Transplantation CEA.- 2. Carcinoembryonic Antigens of the Liver Tumors - Alpha-Globulin.- 3. Carcinoembryonic Antigens of the Digestive Tract (Gold).- VII. Clinical Significance of Carcinoembryonic Antigens.- 1. Diagnostic and Prognostic Value.- 2. Prospective Immunotherapeutic Uses of Carcinoembryonic Antigens.- VIII. Appendix: Methods of Detection, Separation and Purification of Carcinoembryonic Antigens.- 1. Alpha Fetoprotein.- 2. CEA of the Digestive Tract (Gold).- IX. References.