I picked up a copy of Looking for Mr. Goodbar from the New York Public library, and the copy in circulation is an actual first edition of the novel, as shown.
After looking on Amazon.com, I realized there was a new edition with a much more enticing cover.
While I am a huge fan of illustration, I really think the newer version captures the concept of the book much better. First of all, when I think of the aesthetic from the 1970s, my initial reaction is to roll my eyes. Men with perms, macrame plant holders, and orange and brown plaid do not paint a pretty picture for me. However, there was work of Yves Saint Laurent, brilliant films like Network, and a font called Avant Garde.
The font was designed by font pharaoh Herb Lubalin. Its geometric simplicity allows it to be used without distraction when used in its regular set, but takes on a whole new look when using the alternative and ligature set. With the black setting the tone for the novel's gruesome ending, and the image behind the type flickering in and out like a disco ball, it does a much better job of expressing the tone than the the softly-colored sketch in a Family Circus frame.
Apparently the style of overlapping letters is still alive and well. The New York campaign for going green seems to have been inspired by this retro type treatment.