Brookhaven National (BNL) Laboratory is a multidisciplinary laboratory that carries out basic and applied research in the physical, biomedical, and environmental sciences, and in selected energy technologies. It is managed by Brookhaven Science Associates, LLC, under contract with the U.S. Department of Energy. BNL's total annual budget has averaged about $460 million. There are about 2,800 employees, and another 4,500 guest scientists and students who come each year to use the Laboratory's facilities and work with the staff. The BNL Laboratory Directed Research and Development (LDRD) Program reports its status to the U.S. Department of Energy (DOE) annually in March, as required by DOE Order 4 13.2A, ''Laboratory Directed Research and Development, '' January 8, 2001, and the LDRD Annual Report guidance, updated February 12, 1999. The LDRD Program obtains its funds through the Laboratory overhead pool and operates under the authority of DOE Order 413.2A. The goals and objectives of BNL's LDRD Program can be inferred from the Program's stated purposes. These are to (1) encourage and support the development of new ideas and technology, (2) promote the early exploration and exploitation of creative and innovative concepts, and (3) develop new ''fundable'' R & D projects and programs. The emphasis is clearly articulated by BNL to be on supporting exploratory research ''which could lead to new programs, projects, and directions'' for the Laboratory. As one of the premier scientific laboratories of the DOE, BNL must continuously foster groundbreaking scientific research. At Brookhaven National Laboratory one such method is through its LDRD Program. This discretionary research and development tool is critical in maintaining the scientific excellence and long-term vitality of the Laboratory. Additionally, it is a means to stimulate the scientific community and foster new science and technology ideas, which becomes a major factor in achieving and maintaining staff excellence and a means to address national needs within the overall mission of the DOE and BNL. The LDRD Annual Report contains summaries of all research activities funded during Fiscal Year 2004. The Project Summaries with their accomplishments described in this report reflect the above. Aside from leading to new fundable or promising programs and producing especially noteworthy research, the LDRD activities have resulted in numerous publications in various professional and scientific journals and presentations at meetings and forums. All FY 2004 projects are listed and tabulated in the Project Funding Table. Also included in this Annual Report in Appendix A is a summary of the proposed projects for FY 2005. The BNL LDRD budget authority by DOE in FY 2004 was $9.5 million. The actual allocation totaled $8.5 million. The following sections in this report contain the management processes, peer review, and the portfolio's relatedness to BNL's mission, initiatives and strategic plans. Also included is a metric of success indicators and Self Assessment.