This fourth and apparently final episode in the Atreides saga--following Dune (1965), Dune Messiah (1969) and Children of Dune (1976)--is a fatalistic, somber, typically complex creation which manifests something of the structure of a Bach fugue (a parallel which Herbert clearly intended). 3500 years have passed since the death of Paul Atreides and the accession of his son Leto II: the ecological transformation of Dune is complete, with crops, forests and seas obliterating the desert; the sandworms have vanished, ending ""melange"" (addictive geriatric spice) production; the God Emperor Leto broods in his citadel as he slowly metamorphoses into Shai-Hulud, the fearsome giant sandworm of old Dune. So now there's a dullish peace throughout the Empire, rigidly enforced by the Emperor's ruthless control of the remaining melange and his omniscient, oracular vision. But, while wise old royal majordomo Moneo is convinced of Leto's essentially benevolent intentions, embittered Siona (Moneo's daughter) and bewildered, reincarnated Duncan Idaho (latest in a long line of clones provided by the Tleilaxu for Leto's use) view him as a vicious tyrant to be expunged at all costs. The resulting struggle unfolds at a stately, almost staid pace, with even more talk than usual (tantamount to a lecture at times) and less action. Leto himself, however, gradually emerges as a genuinely tragic hero, accepting (and even abetting) his own approaching doom at the hands of Siona and Idaho--who never fully appreciate the terrible sacrifices Leto has made in order to redeem a humanity of which he is no longer wholly a part. Something of a disappointment in terms of surface action, then--but ultimately profound, poignant and powerful: a fitting end to a series which, its many faults notwithstanding, is unequaled in scope, intelligence, inventiveness, and narrative power.