Something that is perhaps a little more personal, but going by the "true impact" metric it fits: Breaking Negative Thinking Patterns - a Schema Therapy Self-he

Something that is perhaps a little more personal, but going by the "true impact" metric it fits: Breaking Negative Thinking Patterns - a Schema Therapy Self-help and Support Book Short and effective (although it's no substitute for a proper therapist). Well, provided that you can take a step back to get over yourself and be brutally honest about your flaws, and do the exercises even when some may feel silly. Helped me identify the causes of a number of problems of the "why do I keep doing this to myself?" kind. Arguably that is the most important step, since that it is required finally start properly dealing with them. I'm in a much better place thanks to that.