Found in 1 comment on Hacker News
Mithrandir · 2012-09-04 · Original thread
The book is now on Amazon, available for Kindle and in paperback:

Kindle: http://www.amazon.com/An-Introduction-Programming-Go-ebook/d...

Paperback: http://www.amazon.com/An-Introduction-Programming-Caleb-Doxs...

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