Samuel Freeman probably devotes more time than anyone else, in a field that has already become its own cottage industry, to analyzing, compiling, and defending the ideas of John Rawls. I think one of the indispensable secondary literature on Rawls is Freeman’s intellectual/critical biography of Rawls. I would highly recommend this book to anyone who takes seriously Rawls’ body of thought, itself an impressive ouevre and already a bona fide monumental classic in the history of political philosophy.
Thus, I also highly recommend Professor Freeman’s re-write of the entry on “the original position,” a cornerstone concept in Rawls’ philosophy and contemporary political philosophy in general, on the Stanford Encyclopedia of Philosophy. This re-write has been long in the waiting, as the last substantive revision on the topic dates back to 2003. I personally can’t think of a better person with more academic authority to write on this topic. I would recommend this to anyone who is even remotely interested in contemporary Anglophone political philosophy, because you pretty much cannot engage with the topic without having some kind of grasp on the concept of the original position.
The entry is well-written, with lucid prose that does not dumb down an important and nuanced concept. This is about as good of an overview of the concept as you are going to get, if you are not going to read through the primary sources. After having read this entry, you should be versed enough to have a meaningful discussion about the concept.
But really, the Stanford Encyclopedia of Philosophy is an invaluable resource: pound for pound, its entries are written by some of the best people in the field, and although the level of lucidity/complexity varies, a careful reading of the entries should at least provide you with the amount of context you need to make sense of it.