This newest edition of Command at Sea includes the valuable guidance for prospective and commanding officers that has been the hallmark of this book since it first appeared as well as addressing the evolving nature of command at sea. This seventh edition has been updated to incorporate new strategic guidance, examines recent changes in fleet structure, and reflects the Navy's and our nation's return to Great Power Competition amidst China's rising assertiveness and a resurgent Russia's efforts to undermine NATO unity in Europe. Of vital importance, this newest edition includes lessons learned from the collisions of USS Fitzgerald and USS John S. McCain. These tragedies prompted the Navy to initiate a Comprehensive Review of Recent Surface Force Incidents that recommended significant actions pertaining to the training, operating, and equipping of surface ships and crews throughout the force. The book provides additional guidance on joint and combined operations, including the need for cooperation and coordination among interagency players as well as non-governmental organizations (NGOs), both international and domestic. The authors discuss changes in the fleet, including the emergence of recent classes of ships (the Freedom--and Independence-class littoral combat ships and the Virginia-class attack submarines) and the addition of the F-35 Joint Strike Fighter. Finally, the authors provide advice from senior leaders, templates for new commanders to follow as they assume command and a recommended reading list tailored to the challenges and rewards of being a commanding officer.