In his notes to Chapter One, Introduction to his thesis, David Press says:
13: “Future students might be interested in the collection of promptbooks of past productions at Northwestern University, now stored at Deering Library. They are catalogued under the names of individual plays. The promptbooks were made by students in directing classes who were required to record blocking, business, etc. Some directors worked closely with the students who made the promptbooks. Krause said in an interview that she did not always consult with the students who made her promptbooks.”
I find that if one’s computer scouting skills aren’t up to the reference maze, the simplest thing to do is to call up the librarian at NU and ask for help. The number I used was 847-491-7656.