While undertaking research for his best-selling novel
Eye of the Needle, Follett had discovered the true story of the
Nazi spy
Johannes Eppler (also known as John W. Eppler or John Eppler) and his involvement in
Operation Salaam, a non-fiction account of which was published in 1959. This was to form the basis of Follett's
The Key to Rebecca, Eppler being the inspiration behind the character Alex Wolff, and he spent a year writing it, more than the time he took to write his previous novels
Eye of the Needle and
Triple. In contrast, Follett's Wolff – though having a sensual and pleasure-loving side – is completely dedicated to his mission, driven by a curious mixture of German nationalism, Egyptian patriotism and an overwhelming personal ambition. Like the German spy Faber in Follett's earlier
Eye of the Needle, he is supremely intelligent, competent and resourceful, and utterly ruthless – ever ready to kill anyone perceived as threatening him, and preferring to do it silently with a knife. However, towards the end of the book, Wolff displays an increasing sadistic streak absent from Follett's earlier spy. Among other things, Wolff is credited with having crossed the Sahara into Egypt by himself on camel, rather than being ferried there, as was the actual Eppler. To enable Wolff to carry out such an epic feat, Follett provides him with a
Bedouin background. Thus Wolff is thoroughly conversant with three distinct cultures; German, the Egyptian urban elites and the desert-dwelling tribes – the last two as distant from each other as they are from the first. Another major departure is to make Wolff's espionage of far greater strategic significance than Eppler's ever was, making the very outcome of the war – or at least of the North African campaign – hinge on it, and fictionally crediting some of Rommel's main battle victories to information provided by Wolff, having gained access to secret battle plans carried by a
Secret Intelligence Service officer. A departure from cryptologic sense occurs in Follett's title conceit: the "key" or code sequence used to render the Axis spy's messages unreadable by the Allies without it. The author has it as a written down device, available for capture by the wily Major Vandam, but the actual code key imagined by Follett is so simple that a real agent would have simply memorised it, not had it written down for anyone to get hold of. The quote from
Rommel which serves as the book's motto – "Our spy in Cairo is the greatest hero of them all" – is genuine, and the battles of the North African Campaign are described accurately. However, the credit given to information provided by Wolff as decisively helping Rommel's victories – and to Vandam's disinformation in causing his ultimate defeat – is fictional. Reviewer Mary Klein noted that "Not only is the code used in the book based on
du Maurier's
Rebecca, but the book's plot line of romance between Elene Fontana and Major Vandam has some similarity with the plot of the original
Rebecca. In both, a Plebeian girl falls in love with a member of the British ruling class, but feels overwhelmed and overshadowed by the memory of his aristocratic first wife – and in both cases, eventually turns out to be a much better mate than that first wife". ==Reception and success==