We just launched our annual Best Books. It wasn't easy to narrow down the thousands of books we reviewed this year to a few dozen, but we did it. Now we want to know what your favorite book of the year is.

In a tweet with the hashtag #PWbestbooks, tell us the title and author of your favorite 2015 book, and tell us why. You've got to fit that all into one tweet--that's the challenge.

The person whose tweet gets the most retweets wins a complete set of our 2015 top 10 books!

We'll announce the winner in the Nov. 13 edition of our Tip Sheet newsletter. Don't get Tip Sheet already? Subscribe here.

So, what's your favorite 2015 book?