In the meantime, Robert Ryan wrote a serviceable novel, Early One Morning, based on the story. It was a pleasant read at the time, but unmemorable. Someone else published a theory which claimed that Grover Williams survived the War and worked for British intelligence under a different name. The story was in the ether and I feared that someone would pre empt Joe's account.

Joe's Foreword said that he needed convincing to complete the work. As a researcher myself, I think that he knew in his bones that his research was not complete, and would only become complete when secret files were made public under the 50 year rule. I know that he had hoped to get some details from German documents which had been transported to Moscow in 1945.

Joe had most of the story a long time ago, it was his integrity as a researcher which prevented him from rushing into print. What then happened was that the story brewed in his mind for years so he became familiar with every aspect.

A common fault among writers of history is that they feel compelled to add unnecessary detail to prove that they have researched it. They cannot simply say that a candle was lit, they have to tell you something about the candle, perhaps the smell of tallow, whereas it should be as natural as turning on a light switch.

Joe has detail and it is the observation of someone unusually at home with his subject. Early on we get the first Thousand Bomber Raid (on Cologne) and it was on that night that Grover Williams parachuted into France. Some writers would make a fuss about all the logistics. We'd have Merlin engines bursting into life all over East Anglia whereas Joe points out that it was a Saturday night, when people went dancing, but members of Bomber Command were absent from pubs and dance halls.

Something big was going on, but it was noticeable only in small, local, ways until the next day's newspapers. It is that degree of observation which makes this book so compelling.