In the 1940’s and 50’s people started to motorise bicycles, This is an Auto cycle. Similar to how electrobikes are becoming popular today. The motor on this bike is mounted above the front wheel and runs on the tyre. There seems to be a hub brake at the centre of the wheel and what looks like a light that is running off the dynamo effect of the motor. Apparently it was a 50cc engine and ran on a 26:1 ratio of petrol to oil. I didn’t find out much more as I was looking at this picture upside down and couldn’t see the writing about it. These motorised bicycles then turned into mopeds in later years. The book isn’t my hubby’s. I think it’s called the History of Motorcycles, and also had details of many motorbikes including ones such as the Vincent Blackshadow and the Brough Superior which T E Laurence (Laurence of Arabia) was riding when he died in a motorbike accident.