Season 4

The fourth season of Doctor Who ran between 10 September 1966 and 1 July 1967. It starred William Hartnell as the First Doctor in the first two stories and then Patrick Troughton as the Second Doctor.

Overview
Season 4 was a season of major changes for Doctor Who, including some that have influenced the series and franchise ever since.

Most notably, Season 4 saw William Hartnell's First Doctor hand off the baton to Patrick Troughton's Second Doctor in the very first regeneration. When Hartnell announced his plans to leave the series, the show's writers came up with the idea of having the Doctor change his appearance and personality. In 1966, while it was not uncommon for actors to change in ongoing TV and film roles, this was possibly the first time a change in appearance was written into the very nature of the character.

The regeneration (a term that wasn't introduced until some years later) occurred in The Tenth Planet, the second story of the season, which carried double significance in that it also introduced the Cybermen, a recurring menace that would quickly establish itself in a strong second-place position behind the Daleks in the Doctor Who rogues gallery. As for the Daleks, an era ended with the series finale, The Evil of the Daleks, which at the time was expected to be the final Dalek story ever (although a Dalek later made a cameo in 1969's The War Games and the Daleks returned full-time to Doctor Who in 1972's Day of the Daleks).

The season introduced companion Jamie McCrimmon, one of the longest-serving and most popular TV companions. The Highlanders, broadcast this season, marked the end of the writers including occasional "historical serials" which featured no fantastic elements other than the TARDIS crew themselves. The next historical story would not appear until Black Orchid was broadcast in 1982.

For most of the season, the opening sequence, theme arrangement, and logo of the Hartnell era was retained. Beginning with The Macra Terror, however, a new opening sequence was introduced, and along with it a new series logo and a modified arrangement of the theme music (introducing the "electronic spangles" sound and the tape echo effect that would both be retained through to 1980). Most significantly, this new opening established the tradition of showing the current Doctor's face.

Season 4 consisted of nine serials and forty-three episodes, the majority of which are considered lost; as of 2016 this season has the sad distinction of being the only Doctor Who season for which not a single story survives in complete form (although audio recordings exist for all the episodes which has allowed cassette and CD reconstructions of the stories to be commercially released).

It was during Season 4 of Doctor Who that its long-standing rival, Star Trek, first aired on American television.

Along with season 21, it was one of only two seasons of the classic series to have a completely different cast in the final story of the season than in the first story.

Recurring

 * The First Doctor - William Hartnell
 * Ben Jackson - Michael Craze
 * Polly - Anneke Wills
 * The Second Doctor - Patrick Troughton
 * Jamie McCrimmon - Frazer Hines
 * Victoria Waterfield - Deborah Watling

Guest

 * Captain Pike - Michael Godfrey
 * Cherub - George A. Cooper
 * General Cutler - Robert Beatty
 * Barclay - David Dodimead
 * Lesterson - Robert James
 * Grey - David Garth
 * Professor Zaroff - Joseph Fürst
 * Samantha Briggs - Pauline Collins
 * Edward Waterfield - John Bailey
 * Theodore Maxtible - Marius Goring

Stories set during this season

 * Ten Little Aliens (between The Smugglers and The Tenth Planet)
 * Food for Thought (between The Smugglers and The Tenth Planet)
 * The Three Paths (between The Smugglers and The Tenth Planet)
 * Invasion of the Cat-People (between The Power of the Daleks and The Highlanders)
 * The Murder Game (between The Power of the Daleks and The Highlanders)
 * Dying in the Sun (between The Power of the Daleks and The Highlanders)
 * Wonderland (between The Power of the Daleks and The Highlanders)
 * The Roundheads (between The Macra Terror and The Faceless Ones)
 * Resistance (between The Macra Terror and The Faceless Ones)
 * The Forbidden Time (between The Macra Terror and The Faceless Ones)
 * The Selachian Gambit (between The Macra Terror and The Faceless Ones)
 * House of Cards (between The Macra Terror and The Faceless Ones)
 * The Yes Men (after The Highlanders and before The Faceless Ones)
 * The Forsaken (after The Highlanders and before The Faceless Ones)

VHS

 * The Tenth Planet (2000) (with telesnap reconstruction of episode 4)
 * Cybermen: The Early Years (1992) (The Moonbase episodes 2 and 4)
 * Daleks: The Early Years (1992) (The Evil of the Daleks episode 2)
 * The Reign of Terror (2003) (The Faceless Ones episodes 1 and 3)
 * The Missing Years (Included in UK The Ice Warriors Collection (1998), US, The Edge of Destruction and Dr. Who: The Pilot Episode (2001) (The Underwater Menace episode 3)

Loose Cannon VHS releases

 * The Smugglers (1999/2008)
 * The Tenth Planet (1998) (Episode 4 only)
 * The Power of the Daleks (1999)
 * The Highlanders (1999/2007)
 * The Underwater Menace (2005)
 * The Moonbase (2002)
 * The Macra Terror (1998/2006)
 * The Faceless Ones (1998/2009)
 * The Evil of the Daleks (2009)

Download/streaming availability
The 4-episode serial The Underwater Menace is available for purchase through the BBC Store, Amazon Video, Google Play and through the Australian, Canadian, British and American iTunes stores (missing episodes 1 and 4 are presented in this release using photographic stills and a restored soundtrack).

Novelisations

 * The Smugglers
 * Doctor Who and the Tenth Planet
 * The Power of the Daleks
 * The Highlanders
 * The Underwater Menace
 * Doctor Who and the Cybermen
 * The Macra Terror
 * The Faceless Ones
 * The Evil of the Daleks

Audiobooks

 * The Smugglers
 * The Tenth Planet
 * The Power of the Daleks
 * The Highlanders
 * The Underwater Menace
 * The Moonbase
 * The Macra Terror
 * The Faceless Ones
 * The Evil of the Daleks