I'm seeking the textbooks that were released in the 1960's call Unified Modern Mathematics. I'm aware 3 parts of the course exist online but I would like to use them in hard copy form. I find these books highly intuitive if used right. Also, Archive.org has some courses but not all 6. Wikipedia mentions that the publisher Addison Wesley released hard copies. If anyone has any information on how to obtain these books, it would be much appreciated.
In order to help you, we should know which country you are from. In Germany, the library of the MPI in Berlin seems to be the only library where you can find these books, see http://gso.gbv.de/DB=2.1/