The best non-fiction is from John Ashdown-Hill, member of the Royal Historical Society and the Richard III Society. His 2013 book The Last Days of Richard III and the fate of his DNA is superb. The focus is entirely on King Richard during 1485 including a calendar and itinerary for the year plus timetable on Bosworth field. Illustrations are plentiful, and the author describes his work going back 16 generations to find DNA from the last survivor of Richard’s line for comparison with the king’s skeleton.