Looked at that collection. I've read a lot of Austrian stuff and I'd say that Hayek's elaboration of the trade cycle and the dynamics of international currencies are the two greatest works of Austrian Economics. They are not the basics by any means though and are pretty tough going, as hard as reading books on compiler design.

http://mises.org/books/monetarynationalism.pdf

http://mises.org/books/pricesproduction.pdf