This is one of my most favorite books of all time. It's also one I have a hard time recommending, for a variety of reasons.
The premise of the book is (not so) simple. Johnny Truant's neighbor, Zampano, dies, and he discovers an extensive literary analysis of The Navidson Records, a fictional documentary about a family experiencing a non-euclidean house. After analyzing the records left by Zampano and putting them together, they get sent to the editor for publishing. The book is effectively layered in 3 stories: the story of Johnny, of the Navidson Record, and the analysis & context of the record through Zampano's report.
The story is not the only layer of this book, however. In addition to the story, the book itself becomes arranged in an increasingly maze-like manner. One example of this is shown in the image on the right. This sort of text arrrangement has been included under a category of books called "Ergodic Literature". Ergodic literature is defined as "a book which requires "extra effort" to read". House of Leaves is the prime example of these books. Text winds around the page, multiple thoughts traverse pages, backward and forward, text is arranged upside down, sideways, in the corner, and everywhere between. Footnotes with footnotes of their own travel along their own stories.