The Director for Acquisitions and Bibliographic Access at the Library of Congress requested a review of the pros and cons of pre- versus post-coordination of Library of Congress Subject Headings (LCSH). There have been several studies of the pros and cons over the years, most notably by Elaine Svenonius and more recently by Lois Mai Chan and Arlene Taylor/Daniel Joudrey - included as appendices to this report. Briefly stated, pre-coordinated strings provide context, which is needed for "disambiguation, suggestibility, and precision"1 and browsability. Pre-coordinated strings have a sophisticated syntax that can express concepts better than single words, yet also can be faceted by systems to group topics into categories for post-coordinated displays when desirable. Post-coordinated terms have serious limitations for recall, precision, understanding, and relevance ranking....