Peter O'Donnell (born 1920), British cartoon writer and author and creator of Modesty Blaise.

O'Donnell begun to write professionally prior to World War II at the age of 16. From 1938 and during the war he served as a NCO in mobile radio detachment of Royal Signal Corps in 9th army in Persia in 1942. Afterwards his unit was moved to Syria, Egypt, the Western Desert, Italy, and Greece in October 1944.

After the war O'Donnell begun to script comic strips, including the Evening Standard adaptation of the James Bond novel, Dr. No. From 1953-1966 he wrote for Garth and from 1956-1962 Romeo Brown (with Jim Holdaway as an artist). He also wrote for women's magazines, children's papers and an occasional novel.

His most famous creation, Modesty Blaise, was first published in 1963 in comic strip form. O'Donnell later novelized his screenplay for the 1966 motion picture version (which used virtually nothing of O'Donnell's original material). This book was a huge success and O'Donnell would publish about a dozen more novels and short story collections until 1996. He continued to write the comic strip until retiring in 2001.

O'Donnell has also written romance books and television (Take a Pair of Private Eyes) and movie (Revenge of She) scripts. His other famous books are historical romances written under the pseudonym Madeleine Brent.

Books written under the name Madeleine Brent:

• Tregaron's daughter (1971)
• Moonraker's Bride (1973)
• Kirkby's changeling (1975) (also as Stranger at Wildings)
• Merlin's Keep (1977)
• Capricorn Stone (1979)
• The Long Masquerade (1981)
• A Heritage of Shadows (1983)
• Stormswift (1984)
• Golden Urchin (1986)

See the main article on Modesty Blaise for details of his books featuring that character.