You wish to know about the great Mentat School? I would first know from you what is so great about it. That we were forced to contort our bodies and minds into unnatural configurations so that we could find our way out of the primitive wilderness forced upon us by the Butlarian fanatics?
Yes! To become a Mentat is to subvert the very essence of humanity! To rework the human mind on such a fundamental level that it could fulfill the thankless role of a computer in a society that rejected all forms of thinking machine!
The delicious irony, of course, is the persistent rumor that the mind responsible for inspiring the first Mentat was, in fact, a notorious robot scientist and philosopher called Erasmus, an ageless servant of the AI devil.