The Master Mind of Mars is a science fantasy novel by American writer Edgar Rice Burroughs, the sixth of his Barsoom series.

He eventually sold it to publisher Hugo Gernsback for $1,250: only a third of the rate paid by magazines like Argosy All-Story, where the previous book in the series had first appeared.

On Mars, Paxton is taken in by elderly mad scientist Ras Thavas, the "Master Mind" of the title, who educates him in the ways of Barsoom and bestows on him the Martian name Vad Varo.

But Paxton has fallen in love with Valla Dia, one of Ras' young victims, whose body has been swapped for that of the hag Xaxa, Jeddara (empress) of the city-state of Phundahl.

A quest for that body ensues, in which Paxton is aided by others of Ras' experimental victims, and in the end he attains the hand of his Valla Dia, who in a happy plot twist turns out to be a princess.

Burroughs vision of Mars was loosely inspired by astronomical speculation of the time, especially that of Percival Lowell, who saw the planet as a formerly Earthlike world now becoming less hospitable to life due to its advanced age,[2] whose inhabitants had built canals to bring water from the polar caps to irrigate the remaining arable land.