The best motivational book that I've read recently isn't a motivational book strictly speaking, it's The Art of Thinking Clearly by Rolf Dobelli.
You can find his book obviously on Amazon, but it's available widely via free pdf downloads.
I'm not telling you which way to go.
Regardless, I want to point out that this is widely available, whether you pay for it or not.
I can't recommend it enough because as we grow and mature as adults, we tend to pick up negative thinking habits that get really in the way of thinking clearly.
We may be thinking that the way we think is common sense, that is purely natural, and we'd be surprised if other people thought differently.
But in reality, we are actually operating with a lot of logical fallacies and built-in biases that cloud our understanding of the greater world.
This gets in the way of us not only making the best decision but also getting along better with the people around us.
I can't recommend this book enough: The Art of Thinking Clearly.
Let me throw out one nugget that I picked up from this book.
I used to think that if I put in my time, effort, and energy into a decision even though that decision turns out not to be the best one, I should just stick to it because I've already gone this far.
My thinking is that I will somehow recoup the value of my investment if I just stick with my decision long enough.
This turns out to be a waste of resources, time, and most importantly motivational energy because human beings can get burned only so many times before they give up.
When I read the section about this type of logical fallacy, it really opened my mind in terms of how I make decisions and how emotionally invested I get in them.
I suggest you get a copy today because it can really blow your mind.