Read them in published order as there are continuing story arcs within the series.
Killing Floor (1997)
Die Trying (1998)
Tripwire (1999)
Running Blind (2000)
Echo Burning (2001)
Without Fail (2002)
Persuader (2003)
The Enemy (2004)
One Shot (2005)
The Hard Way (2006)
Bad Luck And Trouble (2007)
Nothing To Lose (2008)
Gone Tomorrow (2009)
61 Hours (2010) Worth Dying For (2010)
The Affair (2011)
A Wanted Man (2012)
Never Go Back (2013)
Personal (2014)
Make Me (2015)
Really appreciate the list, thank you!