Alfred Thayer Mahan’s The Influence of Sea Power upon History is well known to students of naval history and strategy, but his other writings are often overlooked when considering today’s challenges. This collection of eight of Mahan’s essays, along with Benjamin Armstrong’s informative introductions and analysis, illustrates why Mahan’s work remains relevant in the 21st century and how that work can help develop our strategic understanding. People misunderstand Mahan, Armstrong reveals, because they have only read what others have to say about him, rather than what Mahan actually wrote. From the challenges of bureaucracy and staff duty, the development of global strategy and fleet composition, and effective leadership included in the first edition, this second edition adds discussions of the United States’ place in the world, the difficulties of naval readiness, and the organization needed for construction of an effective national and naval strategy. With these added essays from Mahan, and a new preface and conclusion analyzing his work from Armstrong, this book demonstrates that Mahan’s ideas about the importance of sea power continue to provide today’s readers with a necessary foundation to address the military and international challenges of the 21st century.