The six articles in this collection commemorate the thirtieth anniversary of the long-awaited publication in 1977 of Christopher Tolkien's edition of The Silmarillion, the first opportunity for most readers to learn more about the detailed mythology and history which underlie, explicitly or implicitly, the narrative of The Lord of the Rings. In view of the long and complex publication history of the texts relating to the legendarium, even thirty years is perhaps too short a time to form a critical consensus about the work. Nevertheless, the articles presented here hope to give a picture of some of the the areas of investigation that have established themselves in that period: mythopoeia, theology, the legacy of the ancient North, and the ways in which a text is created. The contribution by Rhona Beare is a completely re-written version of a section from her now out of print introduction to The Silmarillion; the others have all been written specially for the occasion.