The Art of the American Snapshot is a fabulous collection and history of vernacular photography. This is one of the first books I bought in this direction and it is definitely my favorite because of its diversity of photo techniques and essays, and sheer volume of images.
Another similar, and much smaller text is In the Vernacular. This book also functions like a very select group of images from an exhibition. They also break the images into various categories of archive, proof, surrogate, and yardstick. The images and their functions are explored through these categories.
I've also picked up a few texts on the photo album and its histories and functions. Suspended Conversations is the most recent text that I have purchased. More essays than photos, it looks to be a helpful guide. Snapshot Chronicles: Inventing the American Photo Album runs the other way with photographs of and interpretations of various antique photographs. The book itself invites touch with its green embossed felt cover.