The dashing private investigator, Mark Kilby, experiences adventure mysteries in this series of six titles written by Robert Caine Frazer, one of the pseudonyms for John Creasey

The Mark Kilby series were written between 1959–1964.

• Mark Kilby Solves a Murder (1959) a.p.a. R.I.S.C. (1962), a.p.a. The Timid Tycoon (1966)
• Mark Kilby and the Secret Syndicate (1960)
• Mark Kilby and the Miami Mob(1960)
• Mark Kilby Stands Alone (1962)
• Mark Kilby Takes a Risk (1962)
• The Hollywood Hoax (1964)