“Sky and Ocean Joined: The U.S. Naval Observatory, 1830-2000” by Steven J. Dick is a comprehensive textbook exploring the history and impact of the U.S. Naval Observatory on astronomy and physics. Published by Cambridge University Press in 2007, this hardcover book delves into the significant contributions and advancements made by the observatory in the fields of celestial navigation and scientific research. With 624 pages, this publication offers a detailed account of the observatory’s history, making it an essential resource for students and researchers in the fields of astronomy and physics.