Why bother searching for books if this site itself has a blog dedicated to the subject. You could ask questions there as well should you need to. Here's the link: http://babypips.com/trading/psychology
What's important in trading psychology IMO is actually what's beneath our conscious mind, i.e. our personalities, attitudes, mindsets, etc.; all in the endless ocean of our subconscious minds.
However, what you'll find is that most trading psychology writers writing about problems and solutions that your conscious minds should be able to solve. The ones that are logical and systematic. What's rarely being addressed is our subconscious minds. Why? I don't know and won't dare to speculate. You have to ask them to know their excuses on that.
As you may know, the subconscious minds are the ones who actually in charge when it comes to us making decisions and expressing our emotions. The conscious minds only give reasonings and justifications on the why we do them. So, it's crucial for us traders to know the subject and to know how to deal with them when they give us mental blocks.
So, my point is you may want to look beyond trading psychology books and articles should you need to overcome certain mental challenges. As the root causes may not be related to trading at all. It may come from your past emotional scars that you had buried a long time ago, but now it resurfaces again. Or, it may come from certain mind programming that your family and educators imposed on you creating incompatible mindsets about life, money, business, etc to what a trader should have. Or other reasons whatever they may be. In any case, you need to pin point them and gradually change them.