Interest in the general field of tumor immunology has grown phenomenally in recent years. The number of publications con­ tinues to grow in seemingly exponential fashion and the end is not yet in sight. Under these conditions, it is very difficult for any individual investigator to perceive the whole, or even the small portion within which his own efforts must necessarily be confined. Weare thus very fortunate when an investigator with long and wide experience in the field of tumor immunology takes the time to share his perspectives of a portion of that field. Dr. Koldovsky has been one of the pioneers in tumor immunology and he con­ tinues to contribute, especially in the area of CEA. In the present survey he has reviewed the status of CEA, setting forth not only the literature, but his own interpretation of that literature. For this endeavor, all workers in tumor immunology will be truely grateful.