The Tripods is a television version of the The Tripods novel series by John Christopher. It was produced jointly by the BBC in the UK and the Seven Network in Australia. The soundtrack was composed by Ken Freeman. The first series of The Tripods, which aired in 1984 and consisted of 13 half-hour episodes written by the renowned creator of numerous radio plays Alick Rowe, covered the first novel, The White Mountains; the second series, which consisted of 12 episodes, covered The City of Gold and Lead. Although a script had been developed for the third television series, it was never produced. The first season was made available on VHS and DVD. In March 2009, the BBC published Tripods - The Complete Series 1 & 2 on DVD. The series introduced several minor changes from the novel, including the shape of the Masters and Tripods, which in the book have tentacles; the fact that the gravity inside the Golden City was artificially increased, which is not mentioned in the series; the introduction of "cognoscs," spiritual life-forms vastly superior to the Masters themselves; and the addition of additional main characters, including love interests for both Will and Beanpole. Few female characters exist in the original text. In an interview for Wordcandy, John Christopher was asked about this, and he responded that at the time he wrote the series, it was commonly recognized that girls would read books with male protagonists, but not vice versa. In addition, he felt that the insertion of a complete family of female characters to the television series was "over the top." In addition, the series is unique for featuring non-humanoid aliens, which was rare at the time.