This report analyzes salary data for all professional staff working in the 123 ARL member libraries during FY2017–2018. Data for 10,518 professional staff members were reported this year for the 114 ARL university libraries, including their law and medical libraries (862 staff members reported by 72 medical libraries and 715 staff members reported by 74 law libraries). For the 9 nonuniversity ARL members, data were reported for 3,259 professional staff members. Beginning, median, and average salaries by race, sex, years of experience, geographic region, and professional position for research, university, law, and medical libraries are covered.