When I was at Penn, Mansfield was one of the most prodigious grant getters in the economics department. When I was entering the Wharton MBA program, I wanted to take the waiver exam in microeconomics and heard that it was based on this book, which I had read rather carefully. When I tried to get an economics professor to sign the form allowing me to take the test, he said it would be impossible to pass and that he would not let me try. He argued that many economics majors from top colleges failed their very difficult waiver exam. I kept arguing with him until I sensed he was getting weary, waited for a moment when his right hand was on the desk near mine, then I thrust the pen into his hand and pushed the form under it to just the right place in one quick movement. He signed and I snatched the paper as politely as I could quickly and thanked him. Moments later he realized that he had done something he did not feel comfortable with and as I walked down the hall he stuck his head out the door and shouted: "All you can do is fail!"
Of the 150 or so who took the test I was one of a handful that passed. Know thy enemy.