Professor Simon Rottenberg, Roosevelt University, 430 South Michigan Ave., Chicago 5, Illinois. March 5 1962 Dear Professor Rottenberg: Thanks for your letter of February 21. As I have to choose the day for a lecture in Chicago so as not to interfere with my duties at New York University, I will be in a position to give you a definite answer concerning the planned lecture only in the second part of September. Please excuse this delay. Kindest regards, Sincerely,