The Demon Breed is a 1968 science fiction novel by James H. Schmitz, originally serialized in Analog in a shorter form as "The Tuvela".

[1] Part of Schmitz's "Hub" sequence, The Demon Breed centers on the conflict between the Parahuans—a "physically powerful, resourceful, technically advanced and fearfully cruel"[2] nonhuman species—and a human-colonized water world.

It was her intelligence and intimate knowledge of her home environment, as well as of science, and of another person involved, that allowed her to intimidate an alien species.

James Blish praised the novel, writing that its protagonist is "very well realized" and that "Schmitz's style is a joy -- precise, flexible, colorful, and frequently witty".

He noted that the novel's title was double-edged, because Schmitz was exploring a theme "dear to the hearts of both Heinlein and Campbell .