Those stamp-sized bookseller labels often found on the rear paste down end paper of old and rare books are often as artistically interesting as the books’ dust jackets; high karat precious gems of graphic design in small settings.
Howard Prouty, of ReadInk Books, has been collecting vintage booksellers’ labels for many years and has put together quite a lovely assemblage on the ReadInk Books website, where he writes:
“I think the pleasure I take from these little things has something to do with a certain dimensionality they add to the mostly-unknown story of a particular book’s previous life. To buy a book unadorned with one of these is, often, to simply buy an “old book”; from the evidentiary front matter, one can usually divine that it was published by this or that company, in a particular year, and so what?
“But the specificity of knowing that it spent some time — perhaps was sold for the very first time — at the Satyr Book Shop (on Vine Street in Hollywood, California)
or The Book Shelf (in The Doctors’ Building) of Cincinnati, Ohio, adds a nice geographical element to its journey to your shelves. (Previous owner’s inscriptions are often good for this as well, and have their own charm — but give me a vintage bookstore label any day!)”
Greg Kindall has an astonishing Gallery of Book Trade Labels on his Seven Roads website, which appears to be international action-central for this sub-genre of book collecting. 
More than 2100 labels from all over the world are displayed, and the collection is highly organized for easy reference.
Dive in.
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Images courtesy of Howard Prouty.