I first encountered the Anglo-Saxon poem Beowulf in my senior year of high school. Being the dutiful little Tolkien fan that I was, I promptly checked out The Monsters and the Critics and Other Essays from the local library. The Monsters and the Critics set my feet on the right path and I've loved Beowulf ever since.
Flash forward. This is the fourth year I've taught Beowulf. Over the past summer, I was beginning to worry that my understanding of Tolkien's argument had gotten a little rusty. I'd studied the poem as part of a larger course of study in Anglo-Saxon history during college and all sorts of things had crept in from other authors -not to mention my own meager thoughts on the poem. With the help of the extended kinship network, I got my hands on a copy of The Monsters and the Critics, but some family friends were also able to track down Beowulf and the Critics for me.
Beowulf and the Critics is a scholarly edition edited by Michael D.C. Drout of two unpublished essays that served as material for the much-condensed The Monsters and the Critics. Delving into this volume unearths the original arguments, nuanced and expanded, that are sketched (albeit with firm, definite lines) in the published work. It's a great chance to watch Tolkien name names, interact with portions of his opponents' texts, and express the limits of his own theories and conjectures. The explanatory essays by Drout are also useful for situating Tolkien's work amidst the broader scope of Beowulf criticism. For fans of Tolkien's fiction, a little reading between the lines of the essays helps to draw out Tolkien's own creative proclivities and sheds light on the greater Tolkienian "project" in works like The Silmarillion, The Hobbit, and The Lord of the Rings.
A final word of caution: Drout's critical edition should not be your first stop for understanding Beowulf, nor is it meant for the casual Tolkien fan. It is a critical edition of unpublished scholarly material and meant first and foremost for academics. That said, Drout does happily acknowledge that the volume will draw the interest of fans of J.R.R. Tolkien, and has not left them out of the reckoning in producing the volume.