There is a lovely anecdote in it, which I am paraphrasing from memory, where Stanley Hooker told Lord Hives that the full-throttle height of a new prototype supercharger would be about 30,000 feet. After a flight test, Lord Hives passes over a piece of paper with one number on it - 29,000+ feet.
I think it was 29,900' - I just finished reading the book a couple of weeks ago. Fantastic read I highly recommend it.