For a good brief overview, Wikipedia has the following link: http://en.wikipedia.org/wiki/Development_of_the_New_Testament_canon that may prove useful.
Some Authors to Consider
If you want a respected secular scholar, Bart Ehrmann's Misquoting Jesus is probably your best bet. I'm not endorsing what he says, and I'm not going to say he is unbiased (he has explicitly rejected his Christian faith and openly wishes others would do the same), but he is well respected and has a good grasp of the chain of events.
In addition to his book, the Teaching Company has a [series of lectures he did on the New Testament and on the Church Fathers (the documents, not the people!) which illustrate the early church development of practice. The "History of Jesus to Constantine" and "Lost Christianities" in particular would probably give you the secular development case the best.
In contrast, Daniel B. Wallace will give a more orthodox understanding of why particular books were accepted, and lend credence to the traditional canon.
A Breif Overview
In general, the best way to understand the "process of canonization" is to understand the unique contribution of each book in the canon to the Bible as a whole. Remember, there was no committee that sat down and said, "This is the authoritative list, and everything else is just a book!" Rather, over time, there was a general consensus amongst Christians as to what really was Scripture, and what wasn't.
Marcion would be a good example. He was one of the first to compile a "canon," and his consisted solely of the letters of Paul, and the Gospel of Luke. He considered the Old Testament to speak of a different god, and thought it useless. What Marcion, thought, however, wasn't nearly as important as the reaction of the majority of Christians in contrast. They said, "No, the Old Testament is part of who God is." The general consensus that Marcionism is heresy was pretty well established by about 200AD, and led most then to accept that the Old Testament is part of the canon.
Similar processes occurred around the adoption of the Johnanine corpus - the Gospel, the letters, etc... Likewise, the Gospel of Thomas - purported collection of 115 of Jesus' sayings - proved to be more Gnostic than Christian, and so it was rejected.
The key point is that all of this happened over time. It isn't until Athanasius' Festal Letter of 367 that we even have the first "complete" canon listed anywhere - and Patristic scholars continued to quote other works for some time as well.
Even today, there are certain Christian authors who are considered "more important" than others. If you asked me to pontificate about who is canonical, for example, I'd want to throw in C.S. Lewis, G.K. Chesteron, Augustine, and a couple of others. David Barton, Joel Osteen, Tim Lahaye, not so much. And, I would clearly reject, say, (and I only speak for myself) anything by Joseph Smith or the Watchtower society. Why do I say that? Because my canon speaks to what is important to me. Many Evangelicals would probably agree with me, and do, as can be shown by what other Evangelicals tell others "should be read." The point is not what I've picked, but rather that the same process was in place 2000 - 1600 years ago.
In the end, Why did the canon close? is really the only remaining question, and that has already been answered elsewhere on the site.
