Looks like this man was more ambitious than the Dutchman I mentioned. 'Geheimauftrag' seems influenced by the modern tendencies in western movie fiction of those days.
De Beer/Miller wrote in a simple, very direct style, a bit like Edgar Rice Burroughs (the author of the Tarzan and John Carter novels). As a child I thought his style was very expressive, but when I re-read a few of his western novels as an adult, it seemed rather awkward, but the storytelling was still decent. His stories were marked by latent, occasionally very disctinct homo-erotic symbolism and I'm quite sure he was homo-sexual. He loved to mention that men wore only trousers and that their upper body was naked. There are, no surprise, hardly any female characters in his novels.