The volume is organized into two parts: The first, Continental Margin, includes the continental shelf, slope, and rise. The second, Deep Seabed, encompasses areas seaward of the continental rise. Mining activities covered in this book include all extractive operations on or below the ocean floor, such as pumping, dredging, or direct access by offshore entries or by land-based tunnels to recover naturally occurring inorganic substances, though not necessarily of inorganic origin. Minerals contained in beach sands lying above the normal high-tide level are excluded. Also not examined is the industrial extraction of minerals from seawater, an important source for various salts and the metal magnesium as well as a potential source for such other metals as uranium. With the deepest gratitude, I acknowledge the assistance of scores of individuals in industry and government in the United States and other countries who provided data, maps and photographs. I also appreciate the many permissions granted to use copyrighted material; Robert G. Burke, Editor of the journal Offshore, and Ben Russak, publisher of the journal Marine Mining, have been especially helpful in this regard. Many redrafted and reproduced illustrations included in this book are the work of Becky Heinzelman, Russell Ault, Pat Taj-Terhani, Frank Martin, and William Lensch, all of Northern Michigan University's Learning Resources Center. Their efforts were skillfully coordinated by Scott Seaman, Assistant director of Learning Resources. Numerous photographic reproductions are the handiwork of Donald Pavloski, Tim Clloway, and Kim Marsh in the University News Bureau's Photographic Department. Jessie Luttenton of the Geography Department's Cartographic Laboratory helped design and draft several maps, and I owe a major debt to my colleague, Professor John P. Farrell, for his advice and direction in the design and preparation of several original maps. Without the frequent and diligent efforts of Dena Bovee, Roberta Henderson, John Drabenstott, and Marsha Larmour, all of the University's Library, I would not have had and access to a multitude of reference items. I am especially grateful to Niki Calloway, Deborah Skehen, Laura Campbell, Myra Vaughan, Connie Del Bello, Jane Potvin, Pat Ogle, and Ruth Bishop for their skill and good humor in deciphering my rough draft manuscript and for typing the final copy.

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