Cloak of Darkness by Helen Macinnes
In a quiet London pub, Bob Renwick, founder of counter-terrorist agency Interintell, is handed a list of names. The Minus List has been compiled by the ruthless executive of an international munitions firm, engaged in training terrorists and arms dealing, and he intends to remove anyone who might get in his way. To be on the list means death for the target, their friends and family, and Renwick's name is third.
On a desperate mission that takes him from New York to Paris, from Zurich to Djibouti, Renwick must unmask his nemesis to save all that he holds dear.