I read the book.
To my mind he dictated and was interviewed to get the work out. Not a piece of writing by him.

Still it was good as it showed how he wanted to be a musician but he had to get a job to survive, keep a wife and family, look after the parents.

It also dealt with the mechanics of killing and how different people faced their end.
If you can find it second hand read it.

For the gun nuts he used a 9mm sub machine gun in a rest. This weapon dated from the first days of their creation in the first world war/1920's and was used for something like 50+ years before replaced with a modern gun.

Orrens