I watched an episode last night on You Tube of "Inside the Actors Stuido" with Gabriel Byrne. Gabriel Byrne is one of my favorite actors. He is from Ireland.

He didn't start acting until he was 29 years old, and he said it was mostly due to having a lack of confidence in himself, of self doubt. Being scared of how he would be seen, scared of failing.
He said that the trick to acting was all to do about confidence, and that the only way to overcome the fear was to just get out there and do it. He said that while it is uncomfortable at first, it does get better.

Byrne never had any formal training in acting, and was all self taught. One day, he just said to himself that he was going to go out and do it... so he did, and auditioned for a show. He landed a main part on the extremely popular Irish TV show "The Riordon's." He didn't hit success in America until he was already in his 30's. You may know him from his role in "The Usual Suspects" or "Stigmata."

If the copy of the book you have is what I'm thinking it is, it had excellent reviews. I think it can help. At one time I considered getting a copy for myself.