Quotations in front matter.

Sequel to Sisterhood of Dune.

Gilbertus Albans has founded the Mentat School, a place where humans can learn the efficient techniques of thinking machines. But Gilbertus walks an uneasy line between his own convictions and compromises in order to survive the antitechnology Butlerian fanatics, led by the madman Manford Torondo and his Swordmaster Anari Idaho. Mother Superior Raquella attempts to rebuild her Sisterhood School on Wallach IX, with her most talented and ambitious student, Valya Harkonnen. Meanwhile, Josef Venport conducts his own war against the Butlerians. The VenHold Spacing Fleet controls nearly all commerce, thanks to the superior mutated Navigators that Venport has created. The Mentats, the Navigators, and the Sisterhood all strive to improve the human race, but each group knows that as Butlerian fanaticism grows stronger, the battle will be to choose the path of humanitys future-whether to embrace civilization or to plunge into an endless dark age.