After leaving school, Dicks studied English at Downing College, Cambridge, and later did two years of National Service in the British Army. Following his discharge from the armed forces, he worked for five years as an advertising copywriter, and began writing radio play scripts for the BBC in his spare time.

His break in television came when his friend Malcolm Hulke asked for his help with the writing of an episode of the popular ABC (ITV) action-adventure series The Avengers, on which Dicks received a co-writer's credit on the broadcast. He also wrote for the popular ATV soap opera Crossroads.

In 1968 he was employed as the assistant script editor on the BBC's popular science-fiction series Doctor Who. Dicks went on to become the main script editor on the programme the following year, and earned his first writing credit on the show when he and Hulke co-wrote the epic ten-part story The War Games which closed the sixth season and the era of Second Doctor Patrick Troughton. He had, however, been the uncredited co-writer of The Seeds of Death earlier in the season, after performing extensive work on writer Brian Hayles' original scripts.

Dicks went on to form a highly productive working relationship with incoming Doctor Who producer Barry Letts, working as the script editor on each of Letts' five seasons in charge of the programme from 1970 to 1974. After his departure, Dicks continued to be associated with the programme, writing four scripts for his successor as script editor Robert Holmes: Robot (1975, the opening story of Tom Baker's era as the Fourth Doctor), The Brain of Morbius (1976, broadcast under the name 'Robin Bland' after Dicks' displeasure at Holmes' rewrites to the story led him to declare that it should go out "under some bland pseudonym"), Horror of Fang Rock and State of Decay.

Dicks also contributed heavily to Target Books' range of novelisations of Doctor Who television stories, writing more than sixty of the titles published by the company. As Dicks explains in an interview in the documentary Built for War, included on the DVD release of the serial The Sontaran Experiment in 2006, he served as unofficial editor of the Target Books line. In this role, he would attempt to enlist the original teleplay author to write the books whenever possible, but if they could not or would not, then Dicks would often end up writing the books himself (although he also enlisted other writers including one-time Doctor Who actor Ian Marter and former series producer Philip Hinchcliffe). On one occasion, Dicks recalls in the documentary, he had enlisted Robert Holmes to novelise his teleplay for The Time Warrior, but when Holmes gave up on the project after writing only one chapter, it was left to Dicks to complete the work. Dicks would be more successful in recruiting the original teleplay writers for later serials and ultimately only had to adapt one Sixth Doctor story (The Mysterious Planet and again replacing Robert Holmes, who had died soon after writing the original serial) and his name appears on no Seventh Doctor novelisations. Dicks had planned to novelise the stage play Doctor Who - The Ultimate Adventure but this was never published.

It was through his work on Doctor Who books that he became a writer of children's fiction, penning many successful titles during the 1970s and 80s.

In 1980 Dicks returned to the Doctor Who fold when he wrote State of Decay for the eighteenth season. State of Decay was in fact a rewritten version of a story entitled The Vampire Mutation which had been due for production during season fifteen, but had been hastily withdrawn and replaced with Horror of Fang Rock when the BBC decided that its vampiric theme would clash with their high-profile adaptation of Bram Stoker's Count Dracula, which was due for transmission at around the same time. Dicks made his final contribution to televised Doctor Who in 1983, when he wrote the ninety-minute twentieth anniversary special episode The Five Doctors.

During the early 1980s he worked again as script editor to Barry Letts' producer, this time on the BBC's esteemed Sunday Classics strand of period dramas and literary adaptations. When Letts departed the staff of the BBC in 1985, Dicks succeeded his colleague as the producer of the strand, overseeing productions such as Oliver Twist, David Copperfield, and Vanity Fair, before he himself left in 1988 and the Sunday Classics strand in that form came to an end.

During the 1990s, Dicks contributed to Virgin Publishing's line of full-length, officially-licensed original Doctor Who novels, the New Adventures, which carried on the story of the series following its cancellation as an ongoing television programme in 1989. Dicks wrote three Doctor Who novels for Virgin, and continued to write occasionally for the franchise following the take-over of the books licence by BBC Books in 1997. He wrote the first of the Eighth Doctor Adventures, The Eight Doctors, which was for a time the best-selling original Doctor Who novel. His book World Game, featuring the Second Doctor is set during "Season 6B", a period derived from fan theories. His most recent contributions to the range are the "Quick Reads" books Made of Steel and Revenge of the Judoon, both featuring the Tenth Doctor and Martha Jones.

Other work has included two Doctor Who stage plays (Doctor Who and the Daleks in the Seven Keys to Doomsday (1974) and Doctor Who - The Ultimate Adventure (1989)); co-creating and writing for the short-lived BBC science-fiction series Moonbase 3 (1973) and contributing to the ITV science-fiction series 1999. He also wrote an audio drama for Big Finish Productions called "Comeback", which was the first to predominantly feature former companion Sarah Jane Smith. That story was released in August 2002.

In 1976, Dicks wrote a trilogy of books published by Target Books called "The Mounties" about a recruit in the Royal Canadian Mounted Police. These were followed in 1979—1983 by another Target trilogy "Star Quest", which were later reprinted by Big Finish Productions.

Starting in 1978, Dicks began a series called "The Baker Street Irregulars" which eventually ran to ten books, the last being published in 1987. In 1981, Dicks also began a series of six children's horror novels with "Cry Vampire", coinciding with his novelisation of the Doctor Who serial State of Decay in which vampires also featured heavily.

1987 saw Dicks start a new series of books for very young children called "T. R. Bear", amounting to a further seven books. These were followed by the "Sally Ann" series about a determined ragdoll, "Magnificent Max" about a cat and "The Adventures of Goliath" about a golden retriever. The Goliath series is Dicks' largest amounting to eighteen books. Another five books about a St. Bernard dog made up the "Harvey" series.

"Jonathan's Ghost" and three sequels were published in 1988, and the three book "MacMagic" series followed in 1990. "The Littlest Dinosaur" was published in 1993 and "The Littlest on Guard" in 1994. Other works published in 1994 include "Woof! the Never Ending Tale", the "Cold Blood" series (four books), the "Chronicles of a Computer Game Addict" (four books).

Between 1998 and 2000 Dicks produced the three novel "Changing Universe" series. Since then, Dicks has been engaged in the ongoing "The Unexplained" series with twelve books so far.

As well as the vast number of fictional works, Dicks has also written several non-fiction books for children including "Europe United", "A Riot of Writers", "Uproar in the House", "A Right Royal History" and "The Good, the Bad and the Ghastly".

Dicks currently resides in Hampstead, London. He is married and has three sons.

• Great March West (1976)
• Massacre in the Hills (1976)
• War Drums of the Blackfoot (1976)
• The Case of the Missing Masterpiece (1978)
• Spacejack (1978)
• The Case of the Blackmail Boys (1979)
• Roboworld (1979)
• The Case of the Cinema Swindle (1980)
• The Case of the Crooked Kids (1980)
• The Case of the Ghost Grabbers (1980)
• Cry Vampire! (1981)
• The Case of the Cop Catchers (1981)
• Terrorsaur! (1981)
• Ask Oliver (1982)
• Marvin's Monster (1982)
• Wereboy! (1982)
• The Mystery of the Missing Diamond (1983)
• Demon of the Dark (1983)
• The Fireworks Mystery (1984)
• The Mystery of the Missing Train (1984)
• Goliath and the Dognappers (1984)
• Ghosts of Gallows Cross (1984)
• Gupta's Christmas (1985)
• Goliath on Holiday (1985)
• Goliath at the Dog Show (1986)
• Goliath's Christmas (1986)
• T.R. Afloat (1986)
• T.R.'s Hallowe'en (1986)
• In the Money (1986)
• The Disappearing Diplomat (1986)
• The Case of the Fagin File (1987)
• Goliath and the Burglar (1987)
• Goliath and the Buried Treasure (1987)
• Goliath Goes to Summer School (1987)
• Goliath on Vacation (1987)
• Goliath's Easter Parade (1987)
• Goliath at the Seaside (1988)
• T.R's Big Game (1987)
• T.R.'s Festival (1987)
• Sally Ann, on Her Own (1987)
• By the Sea (1987)
• School Fair (1987)
• The Criminal Computer (1988)
• The Haunted Holiday (1988)
• Goliath Cub Scouts (1989)
• Enter T.R. (1988)
• T.R. Bear: Enter T.R., T.R. Goes to School, T.R.'s Day Out, T.R.'s Halloween (1988)
• T.R. Goes Skiing (1988)
• T.R. Goes to Hollywood (1988)
• T.R. Goes to School (1988)
• T.R.'s Day Out (1988)
• The Picnic (1988)
• Sally Ann Goes to Hospital (1988)
• Sally Ann's School Play (1988)
• In Trouble (1988)
• A New Beginning (1988)
• Goliath's Sports Day (1989)
• T.R. Down Under (1989)
• T.R. in New York (1989)
• At the Ballet (1989)
• The River Rats (1989)
• The School Spirit (1989)
• Spitfire Summer (1989)
• Magnificent Max (1989)
• Goliath and the Cub Scouts (1990)
• Goliath's Birthday (1990)
• Teacher's Pet (1990)
• T.R. Bear at the Zoo (1990)
• The Pony (1990)
• Majestic Max (1990)
• Max and the Quiz Kids (1990)
• Meet the MacMagics (1990)
• My Brother the Vampire (1990)
• Lost Property (1990)
• Prisoners of War (1990)
• The Winjin' Pom (1991)
• The Big Match (1991)
• Goliath Gets a Job (1991)
• Jonathan and the Superstar (1991)
• Jonathan's Ghost (1991)
• Max's Amazing Summer (1991)
• A Spell for My Sister (1991)
• George and the Dragon (1991)
• What's Going On William (1991)
• The Comic Capers (1992)
• Sally Ann and the School Show (1992)
• Max and the Cat Burglar (1992)
• Max and the Missing Megastar (1992)
• Steaming Sam (1992)
• Knightschool (1992)
• War of the Witches (1992)
• On Their Own (1993)
• Goliath and the School Bully (1993)
• Sally Ann and the Mystery Picnic (1993)
• Max's Old-fashioned Christmas (1993)
• The Littlest Dinosaur (1993)
• Nurse Sally Ann (1994)
• The Ultimate Game (1994)
• Killing Time: Cold Blood 2 (1994)
• Littlest on Guard (1994)
• Cyberspace Adventure (1994)
• Woof! the Never Ending Tale (1994)
• Terror in the Swamp (1994)
• World War Two (1995)
• Harvey to the Rescue (1995)
• Escape from Everytown (1995)
• Littlest Disappears (1995)
• Virtual Unreality (1995)
• The Wild West (1996)
• World War One (1996)
• Harvey and the Beast of Bodmin (1996)
• Harvey on Holiday (1996)
• The Wollagong Incident (1996)
• Murder on the Net (1996)
• Jonathan's Ghost: Spitfire Summer, The School Spirit and Jonathan and the Superstar: A Spine-chilling Trilogy (1997)
• Harvey and the Swindlers (1997)
• Harvey Goes to School (1997)
• The Bermuda Triangle Incident (1997)
• The Circle of Death Incident (1997)
• Stella's Wedding (1990)
• Internet Danger (1998)
• The Transylvanian Incident (1998)
• SS World (1998)
• Mets O Hyd (1998)
• The Borley Rectory Incident (1998)
• The Easter Island Incident (1999)
• Mafia Incident (1999)
• The Pyramid Incident (1999)
• Eco Crash (1999)
• Sam the Detective (1999)
• The Chinese Ghost Incident (2000)
• The Mars Project (2000)
• Cassie and the Devil's Charm (2000)
• Sci-fi Danger: Set of 6 (2000)
• Endgame (2000)
• The Bombay Deaths Incident (2001)
• The Inca Alien Incident (2001)
• The Nazi Dagger Incident (2001)
• Cassie and the Conway Curse: Second Sight II (2001)
• Cassie and the Cornish Ghost: Second Sight III (2001)
• Cassie and the Riviera Crime (2002)
• Nikki and the Drugs Queen Murder (2002)
• Star Quest (2003)

Doctor Who

Novelisations

Note: Most of Dicks' Doctor Who novelisations used a 'Doctor Who and' prefix before the title, as did almost all of the novelisations before 1981.

• The Auton Invasion (1974)
• The Day of the Daleks (1974)
• Terror of the Autons (1975)
• The Planet of the Spiders (1975)
• The Three Doctors (1975)
• The Planet of the Daleks (1976)
• The Carnival of Monsters (1977)
• The Claws of Axos (1977)
• The Mutants (1977)
• The Time Warrior (1978) (with Robert Holmes who is uncredited)
• Death to the Daleks (1978)
• The Monster of Peladon (1980)
• Inferno (1984)
• The Mind of Evil (1985)
• The Time Monster (1985)
• Ambassadors of Death (1987)
• The Abominable Snowmen (1974)
• The Web of Fear (1976)
• The Krotons (1985)
• The Faceless Ones (1986)
• The Seeds of Death (1986)
• The Wheel in Space (1988)
• The Space Pirates (1990)
• The Giant Robot (1975) (retitled Robot for the 1992 edition) - Dicks also wrote a version for younger readers published as Junior Doctor Who and the Giant Robot published in 1980
• The Loch Ness Monster (1976) (retitled Terror of the Zygons for the 1993 edition)
• The Pyramids of Mars (1976)
• The Revenge of the Cybermen (1976)
• The Genesis of the Daleks (1976)
• The Face of Evil (1977)
• The Brain of Morbius (1977) - Dicks also wrote a version for younger readers published as Junior Doctor Who and the Brain of Morbius published in 1980
• The Planet of Evil (1977)
• The Deadly Assassin (1977)
• The Talons of Weng-Chiang (1977)
• The Horror of Fang Rock (1978)
• The Android Invasion (1978)
• The Hand of Fear (1979)
• The Invisible Enemy (1979)
• The Robots of Death (1979)
• The Image of the Fendahl (1979)
• The Destiny of the Daleks (1979)
• The Underworld (1980)
• The Invasion of Time (1980)
• The Stones of Blood (1980)
• The Androids of Tara (1980)
• The Power of Kroll (1980)
• The Armageddon Factor (1980)
• The Nightmare of Eden (1980)
• The Horns of Nimon (1980)
• The State of Decay (1981)
• The Keeper of Traken (1982)
• The Sun Makers (1982)
• Meglos (1983)
• The Dalek Invasion of Earth (1977)
• An Unearthly Child (1981)
• The Smugglers (1988)
• Planet of Giants (1990)
• Four to Doomsday (1983)
• Arc of Infinity (1983)
• The Five Doctors (1983)
• Kinda (1983)
• Snakedance (1984)
• Warriors of the Deep (1984)
• The Caves of Androzani (1984)
• The Trial of a Time Lord: The Mysterious Planet (1987)
• Sarah Jane Adventures - Invasion of the Bane Amazon.co.uk: Invasion of the Bane ("Sarah Jane Adventures"): Books: Terrance Dicks (2007)

Several of Dicks' novels were reprinted in omnibus editions, such as The Adventures of Doctor Who and The Dalek Omnibus. Also in the early 1990s, Star Books issued issued "2-in-1" collections of selected Target novelisations, which included several of Dicks' works.

Original novels

• Exodus (1991)
• Blood Harvest (1994)
• Shakedown (1995)
• Mean Streets (1997)
• The Eight Doctors (1997)
• Catastrophea (1998)
• Players (1999)
• Endgame (2000)
• Warmonger (2002)
• Deadly Reunion (2003) (with Barry Letts)
• World Game (2005)
• Made of Steel (2007) "Quick Reads"
• Revenge of the Judoon (2008) "Quick Reads"

Non fiction

• The Making of Doctor Who (1972, with Malcolm Hulke) - updated edition published in 1976.