Season 4
This season 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.
All Episodes
S4 E1: The Smugglers (1)
S4 E2: The Smugglers (2)
S4 E3: The Smugglers (3)
S4 E4: The Smugglers (4)
S4 E5: The Tenth Planet (1)
S4 E6: The Tenth Planet (2)
S4 E7: The Tenth Planet (3)
S4 E8: The Tenth Planet (4)
S4 E9: The Power of the Daleks (1)
S4 E10: The Power of the Daleks (2)
S4 E11: The Power of the Daleks (3)
S4 E12: The Power of the Daleks (4)
S4 E13: The Power of the Daleks (5)
S4 E14: The Power of the Daleks (6)
S4 E15: The Highlanders (1)
S4 E16: The Highlanders (2)
S4 E17: The Highlanders (3)
S4 E18: The Highlanders (4)
S4 E19: The Underwater Menace (1)
S4 E20: The Underwater Menace (2)
S4 E21: The Underwater Menace (3)
S4 E22: The Underwater Menace (4)
S4 E23: The Moonbase (1)
S4 E24: The Moonbase (2)
S4 E25: The Moonbase (3)
S4 E26: The Moonbase (4)
S4 E27: The Macra Terror (1)
S4 E28: The Macra Terror (2)
S4 E29: The Macra Terror (3)
S4 E30: The Macra Terror (4)
S4 E31: The Faceless Ones (1)
S4 E32: The Faceless Ones (2)
S4 E33: The Faceless Ones (3)
S4 E34: The Faceless Ones (4)
S4 E35: The Faceless Ones (5)
S4 E36: The Faceless Ones (6)
S4 E37: The Evil of the Daleks (1)
S4 E38: The Evil of the Daleks (2)
S4 E39: The Evil of the Daleks (3)
S4 E40: The Evil of the Daleks (4)
S4 E41: The Evil of the Daleks (5)
S4 E42: The Evil of the Daleks (6)
S4 E43: The Evil of the Daleks (7)