The history of the Hercules brand of motorcycles by Leo Keller (in German)
This is a book only for Hercules Motorcycle fanatics, like myself, especially as it is written in German only. I found it through bookdepository.com after first learning of it's existence through a motorcycle FaceBook group of which I am a member. And Leo Keller. Of course it's impossible for me to give a review other than it is a quality book that has many interesting photographs and, with great effort, I may actually struggle to use my 2 years of High School German lessons and try and read the most relevant portions.
The translations that follow were done using Google Document Translate.
Translated from the back cover, a description of the book's origin and purpose.
Past two-wheeler brands retain their good sound, and this also applies to Hercules. Leo Keller is dedicated to the time-honored brand. Because the Nuremberg two-wheeler manufacturers always bought their engines from the Schweinfurt giant Fichtel & Sachs, the engine builders took over Hercules. In the mid-1960s, F&S bought the Zweirad Union, which was formed in 1958 from the DKW, Express and Victoria brands. This extensive documentation describes which brands and models were created in this way and how things continued with the Sachs brand. History, models, technology, sport - finally a complete chronicle of the lost but unforgettable company.
Chapter listings translations. To preview the contents. As best I could!