Byron Katie dramatically changed from years of depression over to being happy and fully in charge of her thinking. I highly recommend that everyone who is interested in the healthiest ways of thinking become at least familiar with her work AND to build it into your life.
Here’s a copy of a post by the well-known Marie Forleo:
Marie Forleo - How Byron Katie’s “The Work” Changed Her Thinking
My discussion on my site: Using Byron Katie - A “True” Way Of Looking At Life And Turning It Around.