I WAS in Bourke, New South Wales – the outback, that most powerful of Australian words – the edge of the world, where the unknown begins. I was having a break from writing Cold Light and I had my backpack and gear with me, intending to do a trek in that hard country, maybe to look at a geological oddity called Mount Gunderbooka, about sixty kilometres south-west of the dwindling township of Bourke. The mountain name carried within it the word ‘book’.