4.0

I thought it was an excellent 'what-if' addition to the Death Note universe. I never saw the movie, so everything in the book was a complete surprise to me, and it certainly didn't disappoint.
I like that L, while still undeniably L, takes more of an action stance in this book. His interactions with that little girl are adorable and bring out a side of him that we never got to see, yet is still believable.
New Wammy's Kids are always fun. I enjoyed the tiny tidbit about Q being the one who programed Watari's data deletion software.
What I really liked about the feel of the book was the strangeness that came with L solving a case post-Kira. That the plot is set after Light's defeat and death completely threw me for a loop.
And that ending was pretty perfect-slipping in Near, the Yagami family and the Task Force, and then ending it peacefully with L an his mentor.
Terrific book; would recommend it to any Death Note fan who has finished the manga series.