James Mills Peirce (1834-1906), Perkins Professor of Mathematics and Astronomy at Harvard University, taught at Harvard University from 1861 until his death in 1906. The James Mills Peirce diary was written while Peirce was an undergraduate student at Harvard from 1849 to 1850. Peirce writes about his entrance to Harvard and various college examinations; many major life events, such as his fifteenth birthday; his religious beliefs and relationship to God; humorous anecdotes about his family; and accounts of various important historical and cultural events. Peirce also delves into the intricacies of various friendships, most notably with "Frank," from whom he appears to desire more than friendship.