Are the two circles on the cover of the book some sort of symbols?
House of Leaves, by Mark Z. Danielewski, is a novel about a haunted house, although that is a very simplistic description. The layout of the book mirrors the labyrinth that lies at the center of the house, and Danielewski uses different fonts, typographic styles, and a non-linear structure to evoke a sense of claustrophobia and dread. The book contains dozens of riddles, clues, strange symbols, and hidden words, adding layers on layers to the mystery of the House itself.
The cover of the book is one of the easier riddles to decipher; the black-on-black background shows a labyrinth diagram that evolves into a Spiral at the center, relating to both the maze of hallways in the book and the Grand Staircase that shifts its height and length depending on circumstance. The Spiral may be a reference to the Golden Spiral used in Mathematics, although the Spiral on the cover is not a true Golden Spiral but rather an equidistant Spiral with connecting lines; these probably represent Stairs.
At the center of the Spiral is a classic Pointed Compass image, showing the four Cardinal Directions, and inside the Eight Cardinal and Ordinal Directions (N,E,S,W -- N,NE,E,SE,S,SW,W,NW). This references the fact that compasses and other methods of finding directional orientation do not work inside the maze. The Compass is reminiscent of those used on Maps to indicate True North; since the maze changes its structure and layout, a Map as seen on the cover would be useless.
The cover itself is slightly smaller than the pages of the book, representing the fact that the House -- and the book -- are larger on the inside than on the outside.
House of Leaves is a very complex book that can be read in several different ways, although the simplest reading method -- that of a film annotated by a researcher -- allows the greatest enjoyment of pure story. The book has grown a life beyond the printed page on the Internet, with many web-pages and forums devoted to debating and deciphering all the mysteries within.