The Whalestoe Letters is Mark Z. Danielewski's "Extended Play" or "single" from his first novel, House of Leaves. The 84-page book takes an excerpt from one of the appendices of House of Leaves, written by one of Danielewski's characters, Pelafina H. Lievre, and adds an introduction from new character Walden D. Wyrtha. Eleven new letters discovered by Wyrtha after the publication of House of Leaves appear in addition to the letters from the aforementioned appendix.

The Whalestoe Letters, like House of Leaves, has several International editions, having been translated and published in English, Dutch, and two versions in French. The Whalestoe Letters extends Danielewski's work to those who may have been apprehensive about picking up the large volume that is House of Leaves.