The Dune Encyclopedia had a couple of articles on the Butlerian Jihad. All of the material was invented for that work -- Frank Herbert's novels only had the bar

The Dune Encyclopedia had a couple of articles on the Butlerian Jihad. All of the material was invented for that work -- Frank Herbert's novels only had the barest shred of explanation of what it was -- but their theory was fairly reasonable, and were consistent with the spirit of his writing. (In summary, a hospital's "self-programming computer" terminated a Bene Gesserit woman's pregnancy; her protests ignited existing tensions against computers and high technology.)