Pascoe makes many excellent points. The invasion, however, would have been much harder if they had had to make the same kinds of treaties as the Europeans had to make in New Zealand with the Maori people. But once Australia was declared terra nullius it was open slather, with a general attitude of 'no intelligent life here, go for it'. Sad. Though if you read the accounts of many early explorers they mention things like being taken to a well-built stone house and being fed on roast duck and cake.
Indeed, in the refuge valley not far from my place, the remnants of those stone houses can still be seen.
May I also recommend the work of Robin Coles, most notably 'The Ochre Warriors'. I have been on some of the trips Coles guided around here, and it was so worth doing.