In his third Strategic Studies Institute (SSI) monograph addressing turmoil in the South China Sea region, retired U.S. Air Force officer Clarence J. Bouchat counters the misperceptions that U.S. landpower plays only a minor or supporting role in what is normally considered a predominately maritime- and air-centric theater. Conventional wisdom's misunderstanding of how modern and future landpower capabilities may influence engagement and operations in semi-enclosed maritime environments may be the cause for landpower being marginalized in these environments, as seen in the original Air-Sea Battle concept or the 2014 Quadrennial Defense Review (QDR). For that reason, I am pleased to present this monograph, which explains the vital role of landpower to engage the forces of other countries, deter aggression, and fight if necessary in pursuit of broad U.S. national interests in the region. In a variety of ways described here, the essential direct support of land force capability to the air and sea services, and other government organizations, is also critical to their success when operating in this theater. As Mr. Bouchat states in his Introduction, landpower "offers important options which can often be applied with lower risk of exacerbating direct conflict. As the only form of military power that covers the full range of military options, from humanitarian assistance to full conventional combat, landpower's flexibility and capabilities help manage both peace and conflict" in the South China Sea. To show how landpower is necessary in this contested region, this monograph briefly explores the concept of landpower and its components-forces viii from the U.S. Army, U.S. Marine Corps, and U.S. Special Operations Command (USSOCOM). It then examines landpower's contributions to potential combat operations through wide area defense and maneuver to deterrence through forward presence and peacetime operations, and security engagement with the region's landpower-dominant allies, partners, and competitors. With this understanding of landpower's capabilities to support national interests in a semi-enclosed maritime environment and recommendations to improve its potential in air-sea environments, the reader will better understand that landpower's supporting and stabilizing role is especially important in a theater like the South China Sea. DOUGLAS C. LOVELACE, JR. Director Strategic Studies Institute and U.S. Army War College Press