Jake,
First of all good thing you’d like to read such books but I would like to make you aware what I think of Ryan’s book.
I had a quick look in it while I was shopping and was not impressed with it for the following reasons:
Diagrams are used when it’s simple to explain, and there is a lack of diagrams/photos when (IMO) they are needed.
He writes no more than two lines about plants. That is no where near enough. You could write half a page about plants and still not include everything.
Of the plants there is only one photo… and that is one that acts as a natural Viagra.

In my opinion your better of getting Lofty Wiseman book, SURVIVAL, Ray Mear or one of the books recommended on this site.

Reinhardt