When I was in grade school, in love with the magical worlds of Harry Potter, The Phantom Tollbooth, The Golden Compass, and any other fantasy novels I could get my hands on, my grandmother bought me a book that would open those worlds to me in new and bigger ways.

The Dictionary of Imaginary Places, published in 1980 and last updated in 2000, is an encyclopedia of magical worlds, from Oz to Wonderland to Macondo to Hogwarts. Each entry includes details about the place, its inhabitants, its rules, and how to get there, as well as beautifully drawn maps and images.

As a kid, I loved poring through the dictionary, revisiting worlds I’d been to and worlds I hadn’t. Today, I like to reference it when I’m helping authors develop their own magical places.

When we’re building fantasy worlds, the utter freedom is an incredible gift, but we’re still grounded by our readers’ need for structure to help them immerse themselves in their new environment. Even the most fantastical magical realms need rules, and the entries in The Dictionary of Imaginary Placesact as templates or guidelines to help us create those structures.

Check out the book (I know it's outdated, but it's more than worth it), and next time you set out to write a story that’s outside the realm of realism, start by writing yourmagical world’s entry in The Dictionary of Imaginary Places.