Larry Hurtado points us to the fact that the earliest Christian scriptural documents themselves - the actual physical manuscripts - may have useful things to tell us about early Christianity and how the first Christians understood the writings that came to be included in the New Testament. Unlike the previous reviewer, I didn't find it that dry; Hurtado writes straightforwardly and in a way which brings out that there are new understandings to be had.
One feature which has long been known, and that Hurtado discusses at some length, is that Christians were the first to use the codex (what we think of as a book) on any large scale, rather than the long scrolls of antiquity. So the question is why? With respect to him, I think he overlooks the significance of a fact he himself gives. He points out that before Christians, the only things which were usually presented as a codex were things like astronomical tables and medical works which you needed to look up frequently, so you could find the part you wanted quickly rather than going through a whole scroll to find the part you want. Surely, that indicates how the first Christians were already using the writings - as things to refer to, and read passages from, rather than works to read from start to finish. In other words, they were from the outset using the early gospels and epistles in much the same way as we use the New Testament today. (When was the last time you read the Gospels from start to finish?) That in turn means (I think) that they recognised the authority of the writings from the outset - to put it another way, the quality of inspiration was immediately obvious. That is a corrective against those who say the scriptures only gradually became accepted.
He has useful things to say about what are called the "nomina sacra" - the fact that the manuscripts rarely write out words like "Jesus", "Christ", "Lord", etc in full - but use abbreviations instead. Since Jews refused to write the divine name, then this indicates that the earliest Christians recognised Christ's full divinity. Again, that's not what is often said.
There wasn't a chapter where I didn't find something new to think about.
In short, Hurtado demonstrates that the physical documents themselves, not just the words, have lessons for us about how things were at the start of the Church. In particular, his evidence shows that the faith formed many of its features a lot earlier than a lot of historians claim. That seems important for our own trust in the scriptures