It's the work of Michael Warren, who gathered every scene from every extant edition and reorganized the resulting spice opera into a more complete narrative. He also removed a few seconds, too, to fix a continuity error.
Contrary to legend, it's apparently not the case that a legendary 4 hour "working" cut of David Lynch's original is out there waiting to be found. So this—which includes the expository picturebook used to help TV viewers figure out what the hell is going on—is likely the longest we'll ever see. [via Digg]
Previously: Dune Without Words.