Barbara Harper-Nelson was once the 19-year-old girlfriend, living in Liverpool, of 22-year-old French airman Francis Usai, who was in the RAF Bomber Command. Amazingly, she kept the letters (over 2,000 pages of correspondence) from this witty and amusing young French airman, exiled from his conquered country and based near York, from where he undertook nightly missions into the horrendous firestorm that was the Battle of the Ruhr.

Along with her own diaries, these letters constitute a unique, evocative, often amusing conversation between young people during a time unprecedented in history and with the daily threat of permanent separation, plus the very regular loss of close friends – 50 per cent of all air crews were killed. The intensity of their love story and the quality of their courage catch at the heart.