A significant portion of the educational process at Princeton takes place outside the classrooms and lecture halls, especially during senior year. All A.B. students (and many B.S.E. students) are required to write a senior thesis, which is a significant, original work usually 80 to 100 pages in length. During the senior year, students take a reduced course load (typically three instead of four courses per semester) to allow time to work on the thesis. They also work closely with faculty members from their department, who serve as advisers. Once complete, a copy of every senior thesis is permanently stored in Mudd Manuscript Library. To prepare for the senior thesis, students write one or two 20-page junior papers ("JPs") in the junior year.

Many students go on to expand and publish their theses; others draw on the knowledge acquired and opinions formed during the research process later in life. The following sampling of senior thesis titles from notable Princeton graduates illustrates this point:

• Former U.S. Senator, NBA star, and Presidential candidate Bill Bradley '65: "On That Record I Stand"—Harry S. Truman's Fight for the Senatorship in 1940
• eBay President and CEO Meg Whitman '77: The Marketing of American Consumer Products in Western Europe
• Musician Stanley Jordan '81: Computer Music and Visual Concert
• Actor Dean Cain '88: The History and Development of the Functions of the Academy of Motion Picture Arts and Sciences
• Teach for America Founder Wendy Kopp '89: An Argument and Plan for the Creation of the Teachers Corporation