The Transforming Human Series (変身人間シリーズ Henshin Ningen Shirīzu), also unofficially known as the "Mutant Trilogy," is a trilogy of science-fiction tokusatsu films produced by Toho from 1958 to 1960. It includes the films The H-Man, The Secret of the Telegian and The Human Vapor.[1] All three films revolve around kaijin, human-like kaiju, that were spawned by some sort of scientific experiment. Although the films do not share continuity, they share many similar premises and themes, and two of them, The H-Man and The Human Vapor, share the same director, Ishiro Honda.