Heretics of Dune by Frank Herbert
From Dune to Rakis to Dune, the wheel turns full circle. From burning desert to green and fertile land and on again to burning desert, the cycle is complete. The people of the Scattering are returning. Amongst them, mysterious and threatening, are the women who call themselves the Honoured Matres, adepts of an ecstatic cult. And on Rakis, become Dune, an ancient philosophy is fulfilled with the coming of the she-seer, Sheeana.