I received my copy of this book the other day. And I've got to say it is even better than I expected.
The story is well-told and very readable and gripping. It describes how the small flotilla of jury-rigged and purpose built ironclad gunboats supported the invasion of the Waikato in 1863. Lots of nice wargaming ideas, with troop landings, bombardments and Maori ambushes.
The illustrations are stunning. Lots of contemporary paintings (many I've never seen before). And some very detailed drawings of the vessels themselves, that would be very inspirational for those making model gunboats, whether for the New Zealand Wars or elsewhere.