Buy the full behaviour set (4 books) and be prepared for all of the behaviour challenges that may come your way.  Nip those negative behaviours in the bud as soon as they rear their head.
 
The books are small - 130 mm x 130 mm so they can be easily popped in a handbag and taken to the park, playgroup or other social setting and used to help reinforce the importance of being a good friend outside the home too.