Carl Barks is a legend in the history of Disney and of comic books. As Michial mentioned, he's particularly beloved in Northern Europe. For example, The Carl Barks Collection, is what looks to be a gorgeous academic set of his works, that was only published in Norway, Denmark, Germany, Finland, and Sweden. Too bad I only read English!
Thankfully, if you are an English reader like me there is Fantagraphics. They are putting out the complete Donald Duck and Scrooge McDuck works that were written and illustrated by Barks - although they are not releasing them in chronological order, which is a little confusing. Also, no commentary as far as I can tell.
And, in great news for me, they are now being released through kindle and comixology, so mea-culpa. Last I checked that wasn't true, but I'm happy to be wrong on that one.