There are digressions into the operation and history of various self-loading rifles and machine guns, as well as commentary on the Webley-Fosbery "Automatic Revolver" ("It is, however, no quicker to load than the Service Revolver, and in the hands of the ordinary individual possesses no advantages over the latter; while the action is easily dislocated by mud or grit, and is therefore unsuited to service conditions.")
Some of the quotes are absolute gems.
On the "Broomhandle" Mauser:
It is the ambition of the average Continental officer to possess a Mauser pistol; ideas of stopping-power do not worry him in the least, and he has little use or need for a good fighting weapon; what catches his fancy is a high-speed, long-range arm that he can carry on his belt with ease - and the Mauser fills this bill exactly.
In America, on the other hand, tastes and requirements are exactly different. The American market is a very critical and exacting one, and there is a long tradition behind it which regards a pistol as first and foremost a fighting weapon, which means above all handiness, balance, and the feel of an arm for quick shooting. To-day, in America, as of old, the man who carries the gun, policeman, criminal, or private citizen, carries his life in the chamber, as it were, of that gun; and he must get there first with it if he is to walk the streets again.
On a French pistol:
It is known as "Le Francais", and is of irreproachable manufacture and finish, unlike most French arms.
On WWI-vintage Spanish pistols:
They are one and all of cheap and nasty appearance, of bad material badly made, and very dangerous to use.
I can't recommend this book highly enough. It is an informed, erudite volume that will help you to understand the differences between the various operating systems, calibers, and mechanical histories of many of the great design families of self-loading weapons, written by someone with hands-on experience of the lot of them. Pre-WWII England was obviously a very different place...