Cosin's work on the history of the canon is unsurpassed, and is the work to be consulted on this subject. It is massive in research and content, and is a thorough refutation of the claims of the papacy concerning the historical position of the church on the canon of Holy Scripture.
Yes, a used copy can be obtained, but only at a very expensive price, around $200 to $300 according to a few used book stores that I've checked. It would be very helpful to see this work republished and made available. But alas, there are only a few of us interested in obtaining such a work; and because of that, most publishers would not be interested. If you are interested enough, you might want to check with a good theological library to see if you can borrow it.
