History of the College of New Jersey (1877). I read Maclean while I was working on The Way of Improvement Leads Home, but this time around I was looking for different things. (My notes from my earlier reading are pretty sketchy. I was basically just looking for references to Philip Vickers Fithian and the Princeton classes of 1771 and 1772).
Maclean was president of Princeton from 1854-1868 and clearly loves the college where he spent his entire academic career. His history borders on hagiography in places (as is the case with most 19th century institutional histories), but it is generally a solid chronicle of college life at Princeton through the Civil War era.
What I like about Maclean is his use of primary sources. While I wish he would have more footnotes, he does reproduce dozens of letters, trustee minutes, and commencement exercises from the eighteenth century. Some of these sources I have not been able to find in archives, making Maclean's work very useful to my project.