All Intensive Purposes

Tim Dunlop, an Australian living in the U.S., says:

When I'm in bookshops here in America, I often keep an eye out for Australian titles. You see quite a few, and I'm sure you can guess which authors tend to show up most often. However, there is one Australian author whose work I see far more often than any other and if that sort of visibility is any guide, then that person is by and away the most successful Australian author in America.

And that author is . . . Garth Nix.

Who? I have a thing for Aussie fiction, and have enjoyed books by Peter Carey, Tim Winton, Murray Bail, Delia Falconer, David Foster, and many others, but I can't say I've ever heard of Mr. Nix. What am I missing?