Sandy Mitchell is a pseudonym of Alex Stewart, who has been a full-time writer since the mid nineteen eighties. The majority of his work as Sandy has been tie-in fiction for Games Workshop's Warhammer fantasy and Warhammer 40,000 science fiction lines. The exceptions have been a novelisation of episodes from the high tech thriller series Bugs, for which he also worked as a scriptwriter under his own name, some Warhammer roleplaying game material, and a scattering of short stories and magazine articles.

His hobbies include the martial arts of Aikido and Iaido, miniature wargaming, role-playing games, and pottering about on the family allotment.

He lives in the North Essex village of Earls Colne, with his wife Judith and daughter Hester.