None whatsoever, especially as his first book wasn't even really the first book in a trilogy in the sense that, say, Northern Lights is - i.e. a book that tied up enough plot lines to give you some sense of closure while also gesturing towards the events to come. It simply ..... stopped, halfway through the adventure, with nothing resolved and the main characters in mortal peril. In other words it was simply one half (or possibly third) of a much longer book - a book that now apparently stands at 1032 pages and counting!