I think your most iconic one should be the Explore Australia : National Parks. I have many guidebooks about Australia or other countries, and this is by far the best : perfect balance between photos, must sees, maps, wildlife/flora, walks, and history. Everybody loves it, especially since the Lonely Planet Australia is so rubbish. I just wished you did some more detailed National Park books about each state, and not just a copy/paste of the general one divided into smaller books. Any future publication of that type ? Oh the outback one is great too, I would love a bigger edition with even more “out of the beaten track” places.