One book I can't get rid of is Eunoia, by Christian Bök. In it, each of the five chapters uses only one of the five vowels. It's annoying to read, but I always enjoy the deliberate literary constraint, how everything is an exercise with the words themselves. Others had less enthusiasm. In my undergrad I remember talking to Garry Geddes about it the one time I met him and he said he thought it was neat but ultimately didn't understand "why". I hope it wasn't a pun. Anyway, I'm glad to see Christian is still hard at work.