Harry Potter and The Half-Blood Prince, by J. K. Rowling

A barrel of fun. Although I found the first three books a bit formulaic, Rowling's style evolved in as the series went on, as the subject matter and the characters got more mature. I find it fascinating that if a young reader starts the series at Harry's age in the first book and reads one volume per year, he or she will find that each successive book will grow alongside the reader's level of maturity. The end is chaotic, fast, breath-taking and, heart-rending. I'm nervously and anxiously waiting for The Deathly Hallows, which I pre-ordered as soon as Amazon allowed me to.