Expeditionary Operations (MCDP #3) establishes doctrine for the conduct of military operations by the U.S. Marine Corps. It describes the Marine Corps as an expeditionary force-in-readiness that is manned, trained, and equipped specifically to respond quickly to a broad variety of crises and conflicts across the full range of military operations anywhere in the world. It emphasizes the naval character of Marine Corps force. This publication also underscores the value of Marine Corps forces as a highly cost-effective option in a wide range of situations, including crises requiring forcible entry. Finally, this publication describes the Marine Corp's key expeditionary concepts.