Toward the end of his life, Miller wrote another installment of the Abbey of Saint Leibowitz saga, Saint Leibowitz and the Wild Horse Woman.[7] A full-length novel (455 pages) significantly longer than its predecessor, it is set in AD 3254, eighty years after the events of "Fiat Lux" but several centuries before "Fiat Voluntas Tua". Suffering from writer's block and fearful the new work would go unfinished, Miller arranged with author Terry Bisson to complete it. Bisson said all he did was go in and tie up the loose ends Miller had left.[40] The novel tells the story of Brother Blacktooth St. George of the Leibowitzian abbey who, unlike Brother Francis, wants to be released from his holy vows and leave the abbey. In addition to recounting his travels as Cardinal Brownpony's personal secretary, the book describes the political situation in the 33rd century as the Church and the Texark Empire vie for power. Miller died before the novel's publication.[40]
Saint Leibowitz and the Wild Horse Woman has been called "Walter Miller's other novel". Reviewer Steven H. Silver points out that this "is not to say that Saint Leibowitz and the Wild Horse Woman does not deserve to be read. It is a fantastic novel, only suffering in comparison to Miller's earlier work".[41]
