The fourth season of British science fiction television series Doctor Who began on 10 September 1966 with the First Doctor (William Hartnell) story The Smugglers and, after a change of lead actor (Patrick Troughton) part-way through the series, ended on 1 July 1967 with The Evil of the Daleks.Polly and Ben depart in the penultimate story The Faceless Ones, and at the end of the season Deborah Watling makes her debut as Victoria Waterfield in The Evil of the Daleks.Peter Bryant joined as associate producer for The Faceless Ones, and replaced Gerry Davis as script editor for the last four episodes of the season.The most complete serial of the season, The Tenth Planet, is missing only its last episode; this serial, as well as The Power of the Daleks, The Underwater Menace, The Moonbase, The Macra Terror, The Faceless Ones and The Evil of the Daleks have had their missing elements recreated with animated episodes using the original soundtrack.^† : Episode is missing During this season the title card for the series was changed for the first time, starting with The Macra Terror.