Season 17
It consisted of five stories, plus the incomplete Shada, unfinished as a result of an industrial strike. Lalla Ward joined as Romana II, and the season is notable for the involvement of Douglas Adams in the writing department. This was the last season to use the traditional Delia Derbyshire "Doctor Who theme" arrangement.
Episodes
1 Destiny of the Daleks (1) Sep 1, 1979 
2 Destiny of the Daleks (2) Sep 8, 1979 
3 Destiny of the Daleks (3) Sep 15, 1979 
4 Destiny of the Daleks (4) Sep 22, 1979 
5 City of Death (1) Sep 29, 1979 
6 City of Death (2) Oct 6, 1979 
7 City of Death (3) Oct 13, 1979 
8 City of Death (4) Oct 20, 1979 
9 The Creature from the Pit (1) Oct 27, 1979 
10 The Creature from the Pit (2) Nov 3, 1979 
11 The Creature from the Pit (3) Nov 10, 1979 
12 The Creature from the Pit (4) Nov 17, 1979 
13 Nightmare of Eden (1) Nov 24, 1979 
14 Nightmare of Eden (2) Dec 1, 1979 
15 Nightmare of Eden (3) Dec 8, 1979 
16 Nightmare of Eden (4) Dec 15, 1979 
17 The Horns of Nimon (1) Dec 22, 1979 
18 The Horns of Nimon (2) Dec 29, 1979 
19 The Horns of Nimon (3) Jan 5, 1980 
20 The Horns of Nimon (4) Jan 12, 1980