Assegai - Wilbur Smith (First edition; special traveller's hardback)

It is 1913 and ex-soldier turned professional big-game hunter Leon Courtney is in British East Africa, guiding rich and powerful men from America and Europe on safaris in the Masai tribal territories. One of his clients is German industrialist Count Otto von Meerbach, who has a company which builds aircraft and vehicles for the Kaiser’s burgeoning army. But Leon had not bargained for falling passionately in love with Eva, the count’s beautiful and enigmatic mistress.

Just before the outbreak of World War One, Leon is recruited by his uncle Penrod Ballantyne, Commander of the British Forces in East Africa, to gather information from von Meerbach.
Leon stumbles on a plot against the British involving the disenchanted survivors of the Boer War. It is only when Eva and von Meerbach return to Africa that Leon finds out who and what is really behind the conspiracy.