"Eye of the Needle" by Ken Follett is a suspenseful spy book that will keep readers on their toes all the way. It grips as climax escalates. It is enjoyable and there's romance.
The plot is based on historical fact. By 1944 the British Intelligence, to deceive the Germans into believing that the D-Day invasion would take place via East Anglia, had assembled and formed a large army in south-eastern England, using barracks of empty shells, imitation rubber and timber ships, false radio signals, and what else, but double agents. Plan is that this would give the actual assault via Normandy a tremendous advantage of surprise. This is where history stops. What follows from here is fiction.
Henry Faber, who reports directly to Adolph Hitler, is the number one cover agent of Germany operating in Britain. His weapon is the stiletto, a short, thin-bladed dagger and he goes by the codename "The Needle." His latest operation is to uncover the Allies' plans for D-Day and to this end, he ruthlessly and brutally kills anyone that goes in his way. He sustains his cold-blooded acts until he is shipwrecked on Storm Island, where he is captivated by an amazing woman, Lucy.
Britain's M15 is up to their tasks too. It is the responsibility of Professor Percival Godliman to prevent "The Needle" from fulfilling his mission. Their "cat and mouse" race is sensational and nail biting, an absolute thriller.