An Encyclopedia of Tolkien doesn’t exactly sound like a page-turner. When you first lay hands on a copy of David Day’s new book, with its embossed leather binding, gold-leaf pages, lavish illustrations, and bookmark ribbon, you might imagine putting it on the shelf next to your Lord of the Rings set, maybe dipping into it occasionally when you’re trying to remember what Meduseld or Umbar was.

Once you start paging through, though, you might just find yourself reading the 544-page volume cover to cover. In hundreds of readable and reasonable concise entries, Day describes the significance and origins of every major character, setting, object, or idea in J.R.R. Tolkien’s fantasy universe — and, conversely, how a host of mythic and real-world stories and events influenced Tolkien.

Even if you only know Lord of the Rings from Peter Jackson’s movies (which the purist Day declines to mention), you may be fascinated to learn that Gandalf’s battle with the Balrog of Moria was inspired by a Norse myth about the epochal battle of Ragnarök, or that the Hobbiton mill was inspired by a real-life Birmingham facility that Tolkien helped restore, or that two of the most epic moments in Lord of the Rings were conceived as improvements upon elements of Shakespeare’s Macbeth, “a play that Tolkien loved to hate.”

Day certainly knows his stuff: he’s the author of a dozen books on Tolkien published across the span of four decades. (Several are available in the Canterbury Classics leather-bound series.) As a result, not only does he know Tolkien’s world in intimate detail, he has a confident and convincing sense of why the author created his custom mythos and why it’s resonated so profoundly with readers around the world. Day’s entry on Middle-earth, located alphabetically in the middle of his encyclopedia, is also at the heart of this argument.

Tolkien always insisted that Middle-earth is our real world — the planet Earth in another incarnation. […] This is the real trick of Tolkien’s Middle-earth: an imaginary time in the real world’s age of myth that had a parallel existence and evolution just before the beginning of the human race’s historical time. Tolkien’s Middle-earth is meant to be something akin to what the ancient Greek philosopher Plato saw as the ideal world of archetypes: the world of ideas behind all civilizations and nations of the world.

Of course Day assiduously links Tolkien’s stories to their inspirations, sometimes very direct and sometimes more indirect, in Norse, Anglo-Saxon, Germanic, and other European myths — as well as the real-world inspirations Tolkien took from his own life, including his British upbringing, his World War I experiences, and his academic surrounds. (The ponderous but powerful Treebeard, Day notes, “was specifically meant as a good-humored lampooning of his friend and colleague C.S. Lewis.)

Day also, though, usefully cites parallels to Tolkien’s tales in stories from Asian and Native American traditions that the author himself would likely not have known, but that help illustrate the universal resonance of Frodo’s quest and all that surrounds it. That includes The Lord of the Rings and The Hobbit (finally, it’s explained: goblins and orcs are the same thing), and also The Silmarillion, “the book that first revealed the immense scope of Tolkien’s vast mythology and cosmos.”

Entries representing Tolkien’s fictional world (Gandalf the Grey, Quickbeam, Wainriders) are interspersed alphabetically with entries describing elements from other worlds, including our own (Fenrir from Norse mythology, the dinosaur quetzalcoatlus, the barrow-ground Wayland’s Smithy). That’s part of what makes the book so engaging to read through in order; then there are the plentiful and beautifully executed black-and-white illustrations by several different artists. Tolkien’s own drawings may be canonical, but images like Lidia Postma’s terrifying Gollum and John Blanche’s epic Battle of Five Armies remind you just how powerfully visual his writing is.

But wait, there’s more! A generous section of end matter includes charts (breeds of hobbit, Durion’s dwarfish lineage), battle maps, and synopses of three key ring stories that influenced Tolkien (the Norse Völsunga Saga, the German Nibelungenlied, and Wagner’s operatic Ring cycle). Finally, a short but compelling essay grounds Tolkien in his time, as the terrible atomic bomb invited all too apt a comparison with the author’s One Ring.

An Encyclopedia of Tolkien is a richly rewarding read for anyone who’s ever cracked The Hobbit or The Lord of the Rings and taken an imaginative voyage to Middle-earth. The book will not only enhance your appreciation of Tolkien’s work, but of peer myth-makers like C.S. Lewis, George Lucas, Philip Pullman, and J.K. Rowling.

A perfect example of Day’s insights comes in his description of Avalon, the isle from Arthurian legend to which the mortally wounded king was carried to be “healed and given immortality.” Day notes there’s a parallel in Galadriel’s destination at the end of the War of the Ring. It’s not King Aragorn, the Charlamagne-like figure who’s Tolkien’s most ostensibly Arthurian character, who gets to sail away with the elves, though: it’s the humble hobbit Bilbo and his adopted nephew.

“Aragorn dies within the mortal world,” writes Day. “The supreme reward of this voyage into the land of immortals is reserved for another. The ‘wounded king’ who sails on the Elf-queen Galadriel’s ship across the Western Sea to the Elven towers of Avallónë is Frodo the Ring-bearer, the real hero of The Lord of the Rings.”

– Jay Gabler