Yotsuba is one of the few manga books, that actually makes me laugh out loud when I read it. It is so funny! In addition, if you like Azumanga Daioh, you'll love this series, as it is the same kind of humour.
If you enjoyed the last two manga volumes, this one does not disappoint. Same great humour and childish antics :) The only bad thing about this series, is that it's so easy to read that I read it within half an hour