For one week only, until September 20th, 2017, you can buy the new ebook release of “Learning CFEngine 3” on Amazon at 50% off its list price, US$4.98 instead of the regular US$9.99.
Get it while it’s hot! Buying the ebook on Amazon gives you access to free updates to the book, so you will get all future versions as well.
(note, the link below now takes you to Leanpub, where the book is published now)