This book isn't going to be of any help if you're building a bike, but if you're interested in bikes in general then this is definitely worth a read.
Dealing with the defection of Ernst Degner (and his family - drugged and in the boot of a car!) to the West, armed with the secrets of making two-strokes go extremely fast. The insight into what life was like behind the ‘Iron Curtain’ is just as interesting as the motorcycling content of the book. I think if you’ve lived all your life in the West, you don’t really appreciate just how much the lives of those behind the ‘Wall’ was controlled by the ‘State’.
Print versions don't currently seem to be available new, and as secondhand versions also seem to be expensive, your best bet is a Kindle version, currently £6.31 from Amazon.