What is the author's style in Heretics of Dune by Frank Herbert?

Heretics of Dune continues Frank Herbert's philosophical investigation of the meaning of life, power and religion. It draws heavily on the mythologies built up in the original trilogy and most particularly in God Emperor of Dune. With the God Emperor (or Tyrant) dead for 1,500 years and humankind swept into a great Scattering, Herbert indulges less than usual in political musings and the religious threads look backwards more than forward.