I have a problem where I look outside myself to try and get self-esteem instead of having it come from within. I want to change this, but not sure where to begin. Do you have any book recommendations?

I guess one additional thing I'll add is I'm very, very averse to the spiritual/woo-woo stuff. I like to keep things down to earth as much as possible. So please no religious texts or things that talk about spirituality. Thank you.