Professor Layton Franchise (Question)

Hi Polynauts,

I wanted to dive into the Professor Layton franchise, but I don't know what game to play first.
On the one hand, I want to play the newest entry (the Azran legacies, which is already out here in EU) on the other hand I'd like to start chronologically (Last Spectre). My Questions are:

Is the Story that important (from one episode to another) so that I absolutely have to start with the first one ?