The hereditary and environmental influences on the genius of Kafka's personality are discussed. His exterior, somatic constitution is represented by photos taken during his lifetime as well as some posthumous, imaginary portraits and sculptures by various, mostly Prague, artists. The concept of the artist's psychic formation - his mental makeup - is documented from his diary, dreams, letters, literary work and reports by his friends. The whole proves his introversion, ambivalence, hypersensitivity, obstinancy, anxieties, behavioral anomalies, a life rich in fantasies and his underestimation of his own literary work. (He speaks about it as an idiosyncrasy, wishing it to be burned after his death.) Some little-known drawings by Kafka complement the picture of his talents and creativity. The psychological and psychopathological roots of his extraordinary position in the cultural awareness of his epoch are discussed.