Torchwood started its life on television as a spin-off from Doctor Who, bringing Captain Jack to join new colleagues in a television series that quickly established itself as fresh and watchable television. Its fourth series, subtitled 'Miracle Day', also moved from the niche channel of BBC3 to metamorphose into an international production between the BBC and the US network Starz. Torchwood has continued to entertain, provoke and attract large audiences and an expanding fandom.

This is the first critical celebration of Torchwood across its four series, considering issues of...