There is an illuminating introduction by Jasper Ridley, including also the introduction to the 1745 edition of the letters, by William Oldys, and plenty of illustrations. The letters themselves are not immensely interesting, but do convey Henry's passion and general intense activity - two of them apparently came with a dead deer attached, personally hinted by the king and sent to Hever for the Boleyns' dinner table. I was pleased to recognise several authentic phrases from the letters in the episode of The Tudors we watched last night (episode 7, the one with the outbreak of sweating sickness and the Pope), so the writers clearly did their research.
A nice little presentation of some primary source material.