In the 1980s he wrote an officially-sanctioned spin-off novel from the popular 1960s television series The Avengers, entitled Too Many Targets. He is also known for his various books connected to the BBC science-fiction series Doctor Who. He has also written novels based upon Star Trek making him possibly the only author to have written officially licensed continuation novels based upon both the Doctor Who and Star Trek franchises.

A friend of the writer Terry Nation, he wrote novelisations of several Doctor Who stories featuring Nation's Daleks for Target Books, reportedly one of the few writers willing to do so due to the large percentage of the author's fee Nation's agents demanded for the rights to use the Daleks. For similar reasons, Peel is one of the few novelists to have used the Daleks in full-length original Doctor Who novels, writing War of the Daleks and Legacy of the Daleks in the Eighth Doctor Adventures range for BBC Books in 1997 and 1998 respectively. Neither novel was particularly well-received by fans of the series, due in part to Peel's rewriting of Dalek history as had been seen on screen in the television series (in particular the destruction of Skaro in Remembrance of the Daleks), to bring their story more in line with Nation's wishes than with how television writers subsequent to Nation had depicted them.

Peel was in fact the first writer ever to have penned a full-length Doctor Who novel featuring the Doctor not to be based upon a televised or radio script, Genesys, when he was chosen by range editor Peter Darvill-Evans to launch the New Adventures range, carrying on from where the then-cancelled television series had left off, in 1991. He later wrote the novel Evolution for their sister range, the Missing Adventures (set during the programme's run with previous Doctors and companions), and also The Gallifrey Chronicles (not to be confused with the final book in Eighth Doctor Adventures series), a compendium detailing the history of the Doctor's home planet.

Peel has also written several original novels based upon Star Trek, and under the pseudonym "John Vincent" wrote a series of novels based upon the TV series James Bond Jr..

• Maniac
• Poison
• Shattered
• Talons
• The Mystery Files of Shelby Woo: Hot Rock
• The Secret of Dragonhome
• The Secret World of Alex Mack: I Spy, Lost in Vegas
• The Young Astronauts: Ready For Blastoff! (written as "Rick North")
• Freedom's Fire (written as "J.P.Trent")

Are You Afraid of the Dark? series

• The Tale Of The Sinister Statues
• The Tale Of The Restless House
• The Tale Of The Zero Hero
• The Tale Of The Three Wishes

Carmen Sandiego series

All published by Western Publishing

• Where In America Is Carmen Sandiego?
• Where In America's Past Is Carmen Sandiego?
• Where In Europe Is Carmen Sandiego?
• Where In Space Is Carmen Sandiego?
• Where In The World Is Carmen Sandiego?
• Where In The USA Is Carmen Sandiego?
• Where In The USA Is Carmen Sandiego Part II?
• Where In Time Is Carmen Sandiego?
• Where In Time Is Carmen Sandiego Part II?

Diadem series

The first six books in this series were originally published by Apple . After the cancellation of the series by Apple (Scholastic), books 1-6 were reprinted by Llewellyn Publications in 2004—2005 and books 7 onwards were published directly by Llewllyn. Also published in French by AdA editions. Called "Les mondes de la magie du Diadème"

1. Book of Names (August 1997. Paperback ISBN 0-590-05947-5, Reprint ISBN 0-7387-0617-5)
2. Book of Signs (August 1997. Paperback ISBN 0-590-05948-3, Reprint ISBN 0-7387-0616-7)
3. Book of Magic (August 1997. Paperback ISBN 0-590-05949-1, Reprint ISBN 0-7387-0615-9)
4. Book of Thunder (Hardback ISBN 0-590-05950-5, Reprint ISBN 0-7387-0614-0)
5. Book of Earth (February 1998. Paperback ISBN 0-590-14965-2, Reprint ISBN 0-7387-0613-2)
6. Book of Nightmares (April 1998. Paperback ISBN 0-590-14966-0, Reprint ISBN 0-7387-0612-4)
7. Book of War (May 2005. ISBN 0-7387-0611-6)
8. Book of Oceans (September 2005, ISBN 0-7387-0748-1)
9. Book of Reality (February 2006. ISBN 0-7387-0843-7)
10. Book of Doom (June 2006, ISBN 0-7387-0842-9)

Doctor Who series

• The Chase
• Mission to the Unknown
• The Mutation of Time
• The Power of the Daleks
• The Evil of the Daleks
• War of the Daleks
• Legacy of the Daleks
• The Gallifrey Chronicles
• Evolution
• Genesys

Eerie, Indiana series

• Eerie, Indiana: Bureau of Lost ISBN 0-380-79775-5
• Eerie, Indiana: Simon and Marshall's Excellent Adventure ISBN 0-380-79777-1

James Bond, Jr. series

All published by Puffin in 1992 and written under the pen name "John Vincent."

• A View To A Thrill
• The Eiffel Target
• Sandblast
• Live And Let's Dance
• Sword Of Death
• High Stakes

Shockers series

Published by Grosset & Dunlap.

• Shockers: Alien Prey
• Shockers: Blood Wolf
• Shockers: Dead End
• Shockers: Ghost Lake
• Shockers: Grave Doubts
• Shockers: Night Wings

Deep Space Nine series

• Objective: Bajor (May 1996, ISBN 0-671-56811-6)

2099 series

1. Doomsday (September 1999, ISBN 0-439-06030-3)
2. Betrayal (November 1999, ISBN 0-439-06031-1)
3. Traitor (January 2000, ISBN 0-439-06032-X)
4. Revolution (March 2000, ISBN 0-439-06033-8)
5. Meltdown (May 2000, ISBN 0-439-06034-6)
6. Firestorm (July 2000, ISBN 0-439-06035-4)

Tombstones series

Published by Pocket Books in 1995.

• Dances With Werewolves
• The Last Drop

Written as "Nicholas Adams"

All published by HarperCollins. "Nicholas Adams" is also the pen name for Debra Doyle and James D. Macdonald. See their pages for more information on them.

• I.O.U. (1991)
• Santa Claws (1991)
• Horrorscope (1992) ISBN 0-061-06109-3

He also wrote some Doctor Who comic stories for Doctor Who Monthly:

• Doctor Who (with John Stokes):
• "Devil of the Deep" (in Doctor Who Monthly #61)
• "The Fires Down Below" (in Doctor Who Monthly #67)