My English teacher has said that it is important to read an author first, before reading her critics, so that one can form an opinion unpolluted by the arguments of others.
Is philosophy like this as well? Should I read Wittgenstein before I read books and articles about Wittgenstein? Should I avoid books which try to summarize the great works of philosophy, in case theirs is a biased interpretation? Philosophy is pretty hard, and I think that few people can be expected to attack _The critique of pure reason_ alone; for the philosophy undergraduate, what should be the role of "secondary" sources?