If you've visited Cornflower today you'll have seen some of the Postcards from Penguin: 100 Book Jackets in One Box, and here are a few more from this interesting and good quality collection. Included are lots of the classic 'striped' covers such as those above, some very well known designs:
and others I have never come across before
such as this attractive Penguin Poetry series from 1963.
What would you do, send them to friends, use them as bookmarks or cards for suitably literary jottings, or as reminders to track down some books you've yet to read?