I'm taking a Wilderness First Responder course so I got this book and read it ahead of time (mainly because I'm so old I have to do twice, what everyone else does once to get it stuck in my brain which seems to rapidly be turning into concrete). At any rate, it's an excellent introduction to the topic of First-Aid in the wilderness and very worthwhile for anyone who is planning on spending any time beyond the quick reach of medical responders.
I've been watching the thru-hikers on the PCT, AT, and CDT, this year on YouTube and Facebook and I've already seen everything from encounters with snakes, to blisters, to broken bones, to twisted ankles, and even an evacuation for emergency surgery due to severe stomach pain, so things happen along the trail that happen every day in the world, but medical care is rarely close, so it pays to be prepared.