This is the second book in an ongoing series.. I read number 4 first and I liked that one, so why not read the start as well? I have read in weird order though [4-2-1] but it doesn't really matter that much if you're clever enough to piece a puzzle.
The way this book is done is very nicely done, with a calendar and each month being a chapter with some sort of theme.
Once I get all the books I will read them in order ;]