It's a great book, and very useful - although as stated above, many new discoveries have been made since the last update, so you have to factor that in. But with that said, it's just about the most comprehensive work on offer, I'd say. A very big heavy book, as might be imagined.
Of course the photographic plates are not of the standard we would expect today, but the written text is superb.
My advice for what it's worth - buy it !!! Don't know what the cost is on e bay Australia, but generally they're not cheap. I got mine for £50 at an auction in 2016 (1964 print)