I'm currently reading all the books in this series back-to-back, so will only say a few words on each. 
 I liked this book more than book 1 (even though I also gave that one 4 stars). This has such a classic "whodunnit" structure and that gives Flavia space to be herself and indulge in some wonderfully underhand investigation tactics (all while dreaming about poisons). 
 I'm going to say it again: if you enjoy classic mysteries/whodunnits and haven't checked out this series yet, you really must. You don't need to start at book 1 (I started at book 4 without realising) but, of course, you get to enjoy Flavia's developing character and knowledge more if you follow the books in the order they were written. 
 On to book 3! :-)