Thirty years ago Tom Clancy was a Maryland insurance broker with a passion for naval history. Years before, he had been an English major at Baltimore's Loyola College and had always dreamed of writing a novel.

His first effort, The Hunt for Red October, sold briskly as a result of rave reviews, then catapulted onto the New York Times bestseller list after President Reagan pronounced it 'the perfect yarn.'

From that day forward, Clancy established himself as an undisputed master at blending exceptional realism and authenticity, intricate plotting, and razor-sharp suspense. He passed away in October 2013.

Mark Greaney is the co-author of three number one Sunday Times bestellers with Tom Clancy: Locked On, Threat Vector and Command Authority.

In his research for these novels, Greaney travelled to seven countries and trained alongside military and law enforcement in the use of firearms, battlefield medicine and close-range combat tactics.

He now writes for the Tom Clancy series of novels alongside Grant Blackwood. He lives in Memphis, Tennessee.