A.J. Quinnell
Philip Nicholson
Creasy, an American middle-aged, broken down, ex-marine, and retired mercenary:

Man on Fire (1980)
Finalist 1981 New Blood Dagger Award
Finalist 1981 Edgar Award for Best Mystery

The Perfect Kill (1992)

The Blue Ring (1993)

Black Horn (1994)

Message from Hell (1996)

Non-series thrillers:

The Mahdi (1981)

Snap Shot (1982)
APA: The Snap (1983)

Blood Ties (1984)

Siege of Silence (1986)

In the Name of the Father (1987)