Overall a really nice review!
But...
I think you should sometimes be a bit more accurate with your quotes!
(seems you were a little too enthusiastic
)
One thing that I noticed - you wrote:
"Did you know that most ninja were members of the samurai clan?"
In fact this is not written in the book - at least I didn't read it. I think you refer to p.13 where it is said "...that several samurai clans were verifiably ninja or had members with ninja-like skills."
Different statement: Some or maybe many but not most of the ninja!
(Would be really hard to find evidence for such a statement...
)
And you wrote: "In fact, shuriken were known as a samurai weapon more than anything"...also a dangerous quote I'd say...
The text-statement that "...authors have also wrongly designated weapons often used by samurai - such as the shuriken and kusarigama - 'ninja weapons' - ..."
does not automatically lead to the conclusion that these were known a lot... Actually I would argue the other way around that it is maybe more likely that they were not known very much because in fact several authors did not know about them and wrote wrong stuff...
Though it is of course correct what is written in the book that they were 'many' samurai using these weapons. Unfortunately there is no statement or given source that tells us how many samurai really used this weapons in relation to the standard-weapons like katana, naginata, yari etc. (which is probably hard to say).