"The User's Guide to the Human Mind" by Shawn T. Smith. It's a self-help book centered around the idea that the best way to cope with undesirable mental phenomena is to observe them with detachement, accept them and move on. Surprisingly, it manages to turn that idea from a vaguely eastern-sounding piece of mumbo-jumbo into something actionable and effective in practice. Well, at least for me it did.

It seems to be based on ideas of Acceptance and Commitment Therapy, which is a recent offshoot of CBT. The book doesn't mention this explicitly -- I'm guessing based on the things it cites and the similarity between it's ideas and the description in the Wikipedia article. And said article contains a longish list of relevant books so chance of successful information acquisition through library infiltration is high.