Harry Potter - Half-Blood Prince
by JK Rowling
Published in 2005 (I finished it on August 01, 2007)
Somewhat weaker than the others, it was still quite entertaining. I did find the clues and structure not as tight as her other books. I did enjoy the experience, but found it really was just the first half of the 7th book. As usual, the relationships came across more interesting than the whole "good versus evil" aspect.

So many books … (you know the rest)