As mentioned before, “Happy Thinking” is about dealing with unhelpful thoughts using psychological “tools”. Of course, the tools one uses to deal with one’s mind are not metal tools, like those a mechanic might use! One cannot open up one’s skull to work on one’s mind (please do not even try!).
Luckily, a more practical option is available to all of us, and that is to use one’s inner voice to “talk” to one’s mind and change how it thinks. The concept of an inner voice is not as unusual as you might imagine. Everyone has an inner voice, which is the voice you use when “thinking” to yourself. The voice that one hears when reading something is one’s inner voice. Right now, it’s your inner voice that you hear as you read this sentence!
Many tools in Happy Thinking utilise one’s inner voice to manage one’s thoughts. It’s sort of like talking to oneself, but doing so inside one’s mind rather than speaking words out loud.