A huge amount of knowledge!!
[Crown Copyright of course. ]
Personally I enjoy the mathematics section, which goes from the very basics of fractions to logarithms within 20 pages.
[off topic]
looking at other documents on that link, 1189 MOD residential properties have been empty for 12 or more months!!!
[topic]
Hence why you can now have a Married Quarter as a singly. (Certainly at some Stations anyway).