Nevertheless, some books such as the Joy of Cooking can be totally different from one edition to the next. I have three, all different. one from the 60s, one 70s and the most recent.
And the New York Times Cookbook, is quite different from the New York Times Cookbook - Revised, with recipes being both added and deleted.
I can't speak to any others, as the only other book we have two editions of is Julia Child et al Mastering the Art, and those seem to be very close.