The charge of the Army Research Laboratory Technical Assessment Board (ARLTAB) is to provide biannual assessments of the scientific and technical quality of the research, development, and analysis programs at the Army Research Laboratory (ARL). The advice provided in this report focuses on technical rather than programmatic considerations. The Board is assisted by six National Research Council (NRC) panels, each of which focuses on the portion of the ARL program conducted by one of ARL’s six directorates. When requested to do so by ARL, the Board also examines work that cuts across the directorates. The Board has been performing assessments of ARL since 1996. The current report summarizes its finding for the 2009-2010 period, during which 96 volunteer experts in fields of science and engineering participated in the following activities: visiting ARL annually, receiving formal presentations of technical work, examining facilities, engaging in technical discussions with ARL staff, and reviewing ARL technical materials. The Board continues to be impressed by the overall quality of ARL’s technical staff and their work and applauds ARL for its clear, passionate concern for the end user of its technology–the soldier in the field–and for ARL’s demonstrated mindfulness of the importance of transitioning technology to support immediate and longer-term Army needs. ARL staff also continue to expand their involvement with the wider scientific and engineering community. In general, ARL is working very well within an appropriate research and development (R&D) niche and has been demonstrating significant accomplishments.