Darren Naish has an interesting article on the evolutionary position of rabbits on his blog. In a comment on that article Steve Sailor offers the following background on the writing of Watership Down:
By the way, the book "Watership Down" is one of the great stories of the English at war. Author Richard Adams was a commando dropped on the far side of the Rhine in Operation Market Garden in September 1944 in Gen. Montgomery's audacious attempt to win the war by Christmas. Unfortunately, the Rhine bridge turned out to be "A Bridge Too Far" and Adams, like Hazel the leader of the rabbits, had to cross the Rhine and lead his men out of German-occupied territory. For a week, they lived the rabbit life, with a thousand enemies, and 25 years later Adams blended that adventure, his boyhood wanderings on Watership Down, and "The Private Live of the Rabbit" into one of the unique accomplishments in English literature.
Now this information may be generally available, but it was new to me. It would have been nice to know it before I read the book. I now feel that have to read it all again.