Well for the period it's set in, the fact is that Thornhill is written as a real man, and acted exactly how he would have realistically acted at that time.
Which makes sense, since this novel is based on real people and real experiences.
The Secret River is set in and near Sidney, Australia, at it's beginning, when it was where Great Britain dumped it's convicts to rid the country of them.
It's a story of colonial settlement, of reaching beyond the circumstances life plants you in and making the most of them. It's a survival story. It is also an interesting little glimpse into Australia's history.
The Secret River is the first in a trilogy, based on the author's family. I'm not certain if I'll read the other two. I would possibly be interested in listening to them on audio, but my library doesn't always have all the books in a set available. If I can't get them from the library, I don't know if I'll pursue reading them or not. I'm curious to hear the rest of the story, but their are so many other books on my wish list, that if I can't get these for free, I probably won't spend money on them in order to finish the story.