3.5 I liked this one even better than the first in the series. You CAN read this as a stand alone and still understand the characters. However I think you have a better appreciation for the character development if you've read the first one. Again, a simple, easy read....not so detailed you get lost. What I call a good beach read. But a good murder mystery. even when you don't think there's a murder.
Just don't think its deep enough for a book club discussion UNLESS you just want to have fun with it.