For a class I'm working with, I recently read James Hogg’s The Private Memoirs and Confessions of a Justified Sinner (this link is to an interesting Google Books copy of the first edition).
Confessions is a book about a book preserved in a grave. The unearthed book consists of a pamphlet augmented by some manuscript pages. To these the published book adds an editor’s introduction, which draws from records and oral testimonies, and a conclusion, which includes the text of a letter that appeared in Blackwood’s Magazine. The mixture of sources and questions about the functions of and interrelationships between each (e.g., oral accounts being influenced by circulation of the pamphlet or its memorial or allegorical contents) create a number of archival and interpretive layers that surround the story at the center of the book.
From the concluding paragraph:
Were the relation at all consistent with reason, it corresponds so minutely with traditionary facts that it could scarcely have missed to have been received as authentic; but in this day and with the present generation it will not go down …
Image: The reputed site of an 18th-century suicide's grave, Scotland (from Wikimedia Commons).