This being the only survival book I have ever read I am not really in a position to judge if it is a good book or not, just surfing over a few reviews on the internet shows me that there are some people who think that there is some things in this book that is inaccurate, but also a lot of people who have a lot of positive things to say about it.
I myself have learned a whole lot of things by reading this book and among the things I have learned a lot of them have come in handy when doing geophysics fieldwork. I often take the book with me and try to learn to get better at identifying the different plants that it talks about when I am working outside in nature anyhow.
This is something I have found is a good way to avoid getting your mind all to much mixed up by being out working all day long every day for months in a row, setting myself a goal to learn something while being out there, something that perhaps is not all to related to the work I am doing. When I am out working with someone who has a lot of knowledge in some field, like for example a forester student who can teach me about trees or someone who knows a lot about birds, then it is a given what it is I am trying to learn. But quite often I am out working on my own or with someone who doesn't have any specific knowledge I am interested in. In such situations trying to get to know new edible or poisonous plants, knots or something like this of which there are plenty to get started with in the book that can be both very good skills to acquire while it also keeps me sane.
Often bringing a book into the field is not practical, but that doesn't keep me from bringing home small samples of plants and trying to identify them in the evening and such
I have found that it is generally a good idea to give it a bit of thought how I am going to stay "sane" if I know that I am going to be on a longer assignment, it actually makes it a lot easier to get the job done and do it well if you have something else to think about than the work itself.