The Index of American Public Library Circulation dates back to 1939, and the Index of American Public Library Expenditures to 1951. These indexes are based on annual reports from a sample of all American public libraries serving more than 25,000 people each. Using the 1982 American Library Directory, the researchers identified 1,586 public libraries that appeared to meet this criterion. A letter requesting data on their total circulation and total expenditures for 1975 and 1980 was sent to each of the identified libraries. Usable data was received from 1,336 libraries (84%). The four figures for each library were entered in a computer file and a list was printed of the rates of change for each series--circulation and expenditures--from high to low. Libraries in a systematic sample (every 50th library) were invited to become members of a new sample for the indexes for the 1980s and to contribute their data for 1981 circulation and expenditures. Based on this sample population, this report is divided into sections on: (1) analyses of the present study procedures; (2) new features of the indexes; (3) tests of accuracy on the U.S. indexes; (4) comparisons of the U.S. indexes with data from England and Canada; and (5) correlations between variables. Findings are detailed in 13 appendices, including tables, and references are provided. (THC)