LITERATE AND SAVVY … BRIMS WITH WARTIME INTRIGUE.
–The Washington Post Book World England 1943. Much of the infamous Nazi Enigma code has been cracked. But Shark, the impenetrable operational cipher used by Nazi U-boats, has masked the Germans’ movements, allowing them to destroy a record number of Allied vessels. Feeling that the blood of Allied sailors is on their hands, a top-secret team of British cryptographers works feverishly around the clock to break Shark. And when brilliant mathematician Tom Jericho succeeds, it is the stuff of legend… .
A TENSE AND THOUGHTFUL THRILLER.
–San Francisco Chronicle Until the unthinkable happens: the Germans have somehow learned that Shark has been cracked. And they’ve changed the code… .
SUSPENSEFUL AND FASCINATING.
–The Orlando Sentinel As an Allied convoy crosses the U-boat infested North Atlantic … as Jericho’s ex-lover Claire disappears amid accusations that she is a Nazi collaborator … as Jericho strains his last resources to break Shark again, he cannot escape the ultimate truth: There is a traitor among them… .

GRIPPING … CAPTIVATING .
–New York Daily News
ELEGANTLY RESEARCHED … Readers will find themselves perfectly placed to experience one of Britain’s finest hours.
–People
SATISFYING … Harris does a crackerjack job here, playing his characters’ lives off historical events in surprising ways.
–Entertainment Weekly
SUSPENSEFUL … FIENDISHLY CLEVER.
–Detroit Free Press