One of the most successful of Germany’s WW1 fighter aces, Berthold shot down 44 allied aircraft – and unsurprisingly led an eventful life, surviving six crashes and enduring lengthy periods of convalescence. Kilduff has done a good service in bringing this gifted pilot to the attention of British readers.

I remember reading Kilduff’s biography of the Red Baron several years ago – this is perhaps the work for which he is best known. His style is slightly esoteric – he certainly knows his way round German archives, and has found some excellent sources for this book. Combats are analysed in forensic detail to decide quite who were Berthold’s victims  (and indeed his assailants)– not always easy in the fog of war, and with fighter pilots’ understandable tendency to ‘over-claim’.

To a British eye, there are three unusual aspects to Berthold’s career. Firstly he was initially trained as a pilot but then mobilised as an observer; secondly the observer, at least in the early stages of the German air force, had command of the aircraft – the pilot was little more than a chauffeur. Lastly, Berthold engineered his own move from bombers to fighters. With his talent and application, Berthold made the transition with apparent ease. One key to his combat success was the degree to which he was always thinking ahead of not only his aeroplane, but also the battle.