Watership Down

In Watership Down, Richard Adams creates a rich world that could easily exist right under our noses.  The world that Adams' rabbits live in is full of dangers and is affected greatly by humans (who are constantly smoking!) as well as domesticated animals and wild ones alike.  Each rabbit in the story has a unique personality and as a whole, the rabbits interact much like you might expect humans to.  Some are leaders and some are followers.  Some are warriors and some are sages.  These characters are what drew me quickly into their world as I followed their adventures.