This document presents data from 122 U.S. and Canadian research libraries that were members of the Association of Research Libraries (ARL) during the 1999-2000 fiscal year. Since 1987-88, the number of preservation programs managed by a preservation administrator has grown irregularly from 66 to around 80 in more recent years. A fluctuating growth in preservation expenditures and staffing across the ARL membership accompanied this development. Preservation expenditures for ARL's 110 reporting member libraries were $85,842,245 in 1999-2000, indicating a slow, irregular increase in expenditures for preservation since 1991-92. Total preservation staff decreased slightly to approximately 1,753 full-time equivalents (FTEs) in 1999-2000. Among the types of conservation treatment, Level 1 decreased slightly and level 2 increased slightly, while Level 3 roughly doubled. Microfilming activity decreased sharply to 87,531 bound volumes, the smallest amount since 1990. External funding for preservation activities increased to $7,128,397. Analysis of core data for all reporting libraries is provided in the "Introduction" for the areas of organizational structure, personnel, expenditures, conservation treatment, and preservation reformatting. The data contained in the "Library Data Tables" that follow are descriptive indices of preservation activities in research libraries, including preservation staffs, expenditures, and productivity. A copy of the ARL preservation statistics questionnaire and instructions, as well as footnotes to the statistics, are included. An appendix lists ARL member libraries. (MES)