 To satisfy the public curiosity about his adventures , Detzner wrote Four Years among the Cannibals , from 1914 to the Armistice , under the German Flag , in the Unexplored Interior of New Guinea . The book brought him fame in Germany and Britain , and he became a sought @-@ after speaker on the lecture circuit . In the 1920s , in addition to several articles and two maps of New Guinea , Detzner published a memoir of his adventures in the Niger valley — In the land of the Dju @-@ Dju : travel experiences in the eastern watershed of the Niger — in 1923 , but it did not achieve the popularity of his previous work . 
