This volume takes a while to pick up, and there's a lot here that is (frankly) boring. But there's a lot of really helpful material. Here are some of my biggest takeaways.
Twentieth century theologians (especially Barth, Brunner, Heppe, Torrance, etc.) have botched their surveys of Reformation and Post-Reformation doctrines of Scripture.
The Scholastics were sophisticated exegetes, despite their reputation among modern biblical scholars.
The primary idea underlying the Reformed doctrine of Scripture was its relevance for believers today; God didn't just speak in the past, he speaks today.
While the inerrancy debate wouldn't occur for over a hundred years after the Late Orthodoxy period, the seeds for the inerrantist position were all sown in the sixteenth through eighteenth centuries.
There was much more continuity between the medieval and Reformed doctrines of Scripture (and its interpretation) than I initially thought.
While the Protestant Scholastics were the ones who really facilitated the move toward a more historical-grammatical hermeneutic, they also essentially snuck most of the Quadriga in through the backdoor (and they were pretty much right to do so).
There's plenty more to this book, obviously. Anybody who's serious about reading into the doctrine of Scripture really ought to pick this book up. Muller surveys more primary sources than the average theologian is ever going have time to get around to.