Could you please recommend the best book showing how the transition in government proceeded from say 1960 to the present day
You will find the details and shelf numbers of books on how apartheid was overcome on SUNSearch on the Library webpage. Type "end of apartheid" in the search box and click on Search. The result you will get consists of the details of more or less 56 physical copies en 9 full text online copies. You can page through these results and look at the table of contents, if available, and decide for yourself which book you suite your needs the best.
If you need additional help please watch the short video to learn how to use SUNSearch to find books in the Library on the How do I find, access and use information effectively: a step-by-step guide.
A site where you can find ratings of books is Amazon.com. Again type "end of apartheid" in the search box and click on go to find the details of books on how apartheid was overcome. I see the book Anatomy of a Miracle: The End of Apartheid and the Birth of the New South Africa by Patti Waldmeir (Mar 1997) received a 5 star rating by users of the site.
Good luck in finding your best book on how apartheid was overcome.