For the beginners, I would advise them to have a look at an article on the Mandal Commission in the Wikipedia. It gives a very good short history on the topic, and in addition covers most of the important points on caste based reservations and the problems on this issue. This topic in Wikipedia is usually sufficient for the casual person wanting to understand the issue of caste based reservations and the history behind it.
There is also an article by Dinkar Sakrikar explaining why he believes that the Mandal Commission report is laudable and just and why India needs Caste based reservations.
S.S.Gill, who was a member of the Mandal Commission,wrote an article The Hindu newspaper's Opinion column in 2003, explaining how "The move to extend reservation to the poor among the forward castes not only goes against the basic concept of affirmative action, it also violates the spirit of the Constitution." He goes on to say that the government brought disrepute to Mandal Commission report by implementing only the most glamorous suggestion i.e. reservation, while completely ignoring the other suggestions in the report.
If you still want to know more about this controversial issue, please download this 81 page PDF file onto your computer and go through it.
"In early September 2001, world television news viewers saw an unusual sight. A delegation from India had come to the United Nations Conference on Racism in Durban, South Africa, not to join in condemnations of Western countries but to condemn India and its treatment of its Dalits (oppressed), as Indians better known abroad as “untouchables” call themselves."
Link: Reservation in India.