House of Leaves is fairly layered. It contains “The Navidson Record,” an analysis of a family’s discovery of a terrible secret in their house, which was apparently compiled and partially edited by a man named Zampano, using various secondary sources including journal articles, magazine articles, books, etc. The main inspiration is a short documentary film called The Navidson Record, created by the husband of the family of that name, which documents the issues and horrors of the house.
A man named Johnny Truant was Zampano’s neighbor, and gained possession of the incomplete book and various materials when Zampano died. He did more editing, and put in a ton of footnotes (some of which go on for pages) that discuss the book, his own life, and how he believes working on the book is affecting his life and sanity.
There are also notes from the (unnamed) editor at the publisher in parts of the book.
There is an appendix called The Whalestoe Letters that consists of a collection of letters written to Johnny by his mother when she was in a mental hospital. She descends into paranoia and starts encoding secret messages into the letters. There is no acknowledgement of the letters by Johnny in the main text or in this appendix, except for a single mark at one point.
There are times when sources are pointed out as not being real (and some of the sources are real in our world), certain people are quoted as never having seen the film when elsewhere it seemed that they had, and occasionally at least one of the editors lies and then admits it to the reader. Plus the original editor, Zampano, makes curious text strikethroughs in red over one particular topic - leaving the material intact to be read, unlike with many obliterated redacted portions. He also buried some anagrams and other coded references within the text.
So you have a documentary film inspiring articles and analyses, which were being compiled by one man into a book/meta-analysis of the situation, (and the experience of which may or may not have led to his death in a somewhat supernatural fashion), which was then edited by a young man who added his own story and his unnerving experiences/mental deterioration that he felt were caused by editing the book, with the publisher’s editor adding occasional commentary/clarification. Throw in an appendix full of coded letters from a madwoman that is tangentially related.
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