Andrew Ellicott Douglass was an American astronomer, educator, and founder of the science of dendrochronology. Douglass was associated with the Harvard College Observatory from 1889 to 1894, and its expedition to Peru; the Lowell Observatories in Flagstaff, AZ from 1894 to 1901; and Mexico from 1896 to 1897. During his time at the University of Arizona (1906-1962), Douglass served as professor, dean, acting president, and first director of the Laboratory of Tree-Ring Research, and also the Steward Observatory.

The collection consists of materials related to Andrew Douglass’s astronomical and tree-ring research, as well as his administration at the Harvard College Observatory, Lowell Observatory, the Laboratory of Tree-Ring Research, and for the University of Arizona. Also included are correspondence, photographs, an unpublished biography, silent films shot by Douglass from 1929 through 1955, typescripts of speeches and manuscripts, lecture notes, and more.