Yes, I have read it when I was really stressed out recently. It was good, I would recommend it. It was recommended to me by a CBT therapist, and although it is a little old fashioned, it was useful for me.
I'm reading it now, about half way through. Yeah, the language is out-dated but it's quite engaging.
And in a way the age of the book enhances its message. All the examples are from The Great Depression and World War II. It helps me because I think, well if those people who had something to fret about successfully rid themselves of worry that way, then so can I!