This report is part of a subseries entitled "Marine Flora and Fauna of the Northeastern United States" which is designed for use by biology students, biologists, biological oceanographers and informed laymen. Contents of this report include: (1) Introduction; (2) Morphology; (3) Systematic Characters; (4) Examination Procedures; (5) Glossary; (6) Key to the Holothurians of the Northeastern United States Inshore and Shelf Waters; (7) Annotated Systematic List; (8) Selected Bibliography; (9) Systematic Index; and (10) Editor's Comments. The holothurian fauna (sea cucumbers) of the east coast of the U.S. from southern New Jersey to Nova Scotia, to depths of 200 m, comprise 21 species in 17 genera and 8 families. An introduction to their biology, their identification and classification are discussed. (MR)