Meditations on Middle-Earth (a collection of thoughts on Tolkien by various authors) is the first title in today's list, but it could well cover the next five books handily, which are in essence religious looks at the "legendarium." Defending Middle-Earth is a look from a "pagan" and ecological point of view, and, I think, supports the critical truism that often you come away from a work with the ideas you brought to it in the first place. The Medieval Reader is not about Tolkien, per se, but about sources (from translations either known to have been read by Tolkien or contemporary with him) of Old and Middle English, Norse, Celtic, and Finnish literature that had influences on him and his work. The Smith and Matthews book is a look at the history of the rights, production, and adaptations of Tolkien's work into other media.
Book Count: 1730.