Conversation so far:
What is Project on the city?
Project on the city was a design school published work Rem Koolhaas did.
What subject was Project on the city about?
It was about urban designing.
Is Project on the city a book?
Project on the city is a collection of Rem Koolhaas's published works.
Was Mutations, The Harvard Design School Guide to Shopping, and The Great Leap Forward written by Rem Koolhaas with help from students?
All three books involved Rem Koolhaas' students analysing what others would regard as non-cities, sprawling conglomerates such as Lagos in Nigeria.

Question: What university was he a professor at?
Self-contained rewrite: What university was Rem Koolhaas a professor at?