This is the first book I've read about Edward III, and it's great. I was a fan of Mortimer's 'The Greatest Traitor' so really looked forward to reading this.
I was not disappointed. Mortimer sticks to his guns about Edward II being alive in Edward III's reign, and explains his motives in light of this. You couldn't get a more different king from Edward II, however, and it is his successful reign, wars in France and the multitude of offspring he has that makes this not only a great book in itself, but an excellent precursor to reading about Richard II, Henry IV and Henry V, as well as the Wars of the Roses (well, obviously!).
I started my history reading with the tudors, and worked my way back. If you are thinking of starting to read popular history, my advice is to start further back, as anglo-saxon and medieval kings and queens are so much more interesting!