Short but pretty nice book about Go language. It was recommended to me and I am really glad that I read it. It is much easier to follow than GoTour and in my opinion sets up much friendlier learning curve. Book is available for free online and on Amazon.
I have learned most in part 9 about Structs and Interfaces. Really interesting is chapter 13 about the Core Packages so I can recommend those two if you already know the basics of the language but want to see more practical usage.
Rating 8/10 (just keep in mind that it is an introductory book)