Today our naval forces enjoy maritime superiority around the world and find themselves at a strategic inflection point during which future capabilities must be pondered with creativity and innovation. Change must be embraced and made an ally in order to take advantage of emerging technologies, concepts, and doctrine; thereby preserving the nation's global leadership. Sea Power 21 has additionally specified unmanned vehicles as force multipliers and risk reduction agents for the Navy of the future. Transformation applies to what we buy as well as how we buy and operate it-all while competing with other shifting national investment priorities. The long-term UUV vision is to have the capability to: (1) deploy or retrieve devices, (2) gather, transmit, or act on all types of information, and (3) engage bottom, volume, surface, air or land targets (See Figure 1-1). The growing use of unmanned systems-air, surface, ground, and underwater is continually demonstrating new possibilities. One can conceive of scenarios where UUVs sense, track, identify, target, and destroy an enemy-all autonomously and tie in with the full net-centric battlespace. UUV systems will provide a key undersea component for FORCEnet, contributing to an integrated picture of the battlespace. Admittedly this vision is futuristic. Even though today's planners, operators, and technologists cannot accurately forecast the key applications for UUVs in the year 2050, this plan provides a roadmap to move toward that vision. Pursuit of this plan's updated recommendations beginning in the year 2004, will place increasingly large numbers of UUVs in the hands of warfighters. Thus, UUVs can begin addressing near-term needs while improving understanding of mid- to far-term possibilities. Even the most futuristic applications can evolve in a confident, cost-effective manner. This confidence is based on several factors: the Sea Power 21 Sub-Pillar capabilities identified here address a broad range of user needs; critical technologies are identified that will enable tomorrow's more complex applications; and key principles and best practices are recommended that provide for a logical, flexible, and affordable development effort.