Ever since the first volume appeared in 1977, people have been divided over Patrick Leigh Fermor’s trilogy in which he describes how, as a very young man, he trudged from Rotterdam to Istanbul. His admirers (of whom I am one) delighted in his ornate prose and his magical evocations of ochre-coloured country houses in Mitteleuropa; his detractors claimed it was absurd and impossible for a man in his sixties and seventies to recall in such minute detail the events of half a century before and that the whole thing was, in effect, a charade. It took a cool-headed biographer to sort things out. Artemis Cooper was a close friend of Leigh Fermor, but she had no qualms about showing how her hero – like so many other writers of memoirs and travel books – had misremembered, embellished, conflated and invented in order to achieve his ends.

All this provided a useful demonstration of the difference between biography and autobiography (of which travel books are a distinguished sub-category). I have published four biographies (with a fifth in the pipeline) and three volumes of memoirs, and I am increasingly convinced that although laymen often confuse them – ‘So