Des R. Dunn
According to Wikipedia: "Dunn was born Robert Desmond Dunn in Mackay, Queensland, but was known as Desmond Robert Dunn or Des Dunn.
Dunn wrote fiction paperback novelettes published by Cleveland Publishing from the late 1950s onward. Each title was 30,000 to 40,000 words long. He wrote four crime titles as Des R. Dunn.
Dunn is best known for western novelettes published under several pseudonyms. Dunn's pseudonyms included: Shad Denver, Gunn Halliday, Adam Brady, Brett Iverson, Matt Cregan, Sheldon B. Cole, Walt Renwick and Morgan Culp. He is known to have written over 400 titles using these pseudonyms. Cleveland Publishing owns the rights to these titles and periodically republishes them - sometimes using a different title.
With Don Haring, Dunn is also believed to have written a number of the 290-300 titles in the Larry Kent detective series, but it is not possible to trace which individual titles can be attributed to each author.
Dunn married and divorced twice and had three children. Dunn died in Brisbane, Queensland aged 73."