It is written in the tone of a guidebook. It assumes all these make-believe lands occupy the same world and are accessible to one other. Like a travel guide, brief descriptions of the geography, history and points of interest are included. There are many maps and illustrations - all drawn in a consistent style - to supplement the text. The authors frequently offer personal advice to aid potential visitors, such as "Though they might be invited to join a Yahoo-hunt, visitors are best advised to avoid any contact with them".
Visiting these places doesn't require a passport; it simply requires a sense of wonder. As a travelogue of the unreal, the Dictionary of Imaginary Places not only opens the door to a whole new world of books and authors, but it is a handy resource for devising a mythological world of your own.