Oh, I got myself started with online resources and was using Go for some months when I got the book - I mostly got it because of the author, to match my "The C programming language". And because I was reasonably fluent with Go, certainly some parts were redundant for my knowledge, but I was very pleasantly surprised how much I still learned from this book and that is why I recommend it. Sometimes it was a little detail in the sample programs which made me say: oh, I had not thought of that.