Beneath the Surface: A Natural History of Australian Caves
Brian Finlayson and Elery Hamilton-Smith (eds).
This book has been out of print for some time, but the publishers have now made it available on a Print-on-Demand (POD) basis. You can buy direct from the Publishers for $49.95 (Australian). Simply log in on http://www.unswpress.com.au/isbn/0868405957.htm
Note that all royalties for this book go to the Australian Museum.