Willard T. Perrin kept this pocket diary while attending Harvard University in 1869. The diary contains supplemental printed information and labeled sections for each date, laid out 3 entries to a page. Perrin wrote irregularly throughout the year; the final pages contain additional notes and memorandums such as addresses, a debate question, an illustrated geometry problem, and Perrin's body measurements.
Most of Perrin's entries pertain to his social life and activities, such as Sunday school and services in Methodist, Congregational, and Unitarian churches. He frequently visited with members of his family and sometimes traveled to Waltham, Lowell, and other Massachusetts towns, often as a member of Harvard's baseball team; the diary records several results from games in which Perrin participated. Perrin sometimes noted events of interest such as a birthday party for his 80-year-old aunt (January 16, 1869), a viewing of the Aurora Borealis (April 15, 1869), the National Peace Jubilee and the dedication of a soldier's monument (July 15-20, 1869), and the inauguration of Charles W. Eliot as President of Harvard University (October 19, 1869).