Triplanetary

Confederate veteran John Carter wakes up on Mars, where low gravity makes him the strongest fighter on a dying planet. First book of the Barsoom series.

Edgar Rice Burroughs

John Carter returns to Barsoom and lands in the one place no Martian ever comes back from. Book two of the series, ending on a famous cliffhanger.

Edgar Rice Burroughs

John Carter chases the captors of Dejah Thoris from the south pole of Mars to the frozen north. It closes the opening Barsoom trilogy.

Edgar Rice Burroughs

A chemist stumbles on a way to release atomic energy and builds a ship that outruns light. Written in 1915 and often called the first space opera.

E. E. Smith

After his bride is murdered at their wedding, Lucas Trask takes a warship and goes raiding among the ruined planets of a fallen federation. Revenge turns into empire building.

H. Beam Piper