In the summer of 2017 a new book was published ''African Kaiser: General Paul von Lettow-Vorbeck and the Great War in Africa, 1914-1918' by Robert Gaudi and was savaged in a British review. Here is a taster:
His story has often been told, and Gaudi — an American ‘freelance writer and historian’ — appears to have consulted only these secondary sources, so reveals nothing new. Furthermore, he frequently misunderstands the sources and repeats their errors. He is certainly not au fait with military detail.
Link:https://www.spectator.co.uk/2017/08/...n-east-africa/

On Amazon.com there are eighty-two reviews, the majority are 5*. See:https://www.amazon.com/African-Kaise...s=Robert+Gaudi

Amazon.co.uk has three reviews and one states:
This account is based on a synthesis of existing works. Hence there is little that is new. The author resorts at times to guesswork and speculation. Nevertheless, it is an engaging book about a superb soldier who led the Allies a merry dance over four years. His troops loved him. He was a genius in the art of bush warfare.
Link:https://www.amazon.co.uk/African-Kai...s=robert+gaudi