There are lots of good, even free, DAISY readers available for Windows, but this is the only one for the Mac. It's still in beta, but you can get the idea and try reading some DAISY books.
Check out this link. It highlights the difference between a "text reader," which many applications provide, and a "book reader" that includes navigation by chapter and page number, the ability to skip parts, and a knowledge of the normal parts of a book (like table of contents, footnotes, sidebar, etc.)