Hi, I am wondering how different the Feynman Lectures editions are. I have the option of getting the 1964,1965, 1970, and 1989 editions. Obviously getting the latest of those editions is the best, however I heard that the 2005 edition is the best edition with all the corrections and the one that CalTech endorses. However that is much too expensive. Will the 1989 edition have substantial disadvantages to the 2005 edition? For some reason I cannot post this in the Science and Math Education forum, so I'm just posting it here.