Note - this is for beginners only. If you are already into R/C or multirotors, you'll want to pass the link onto friends....because the book is to get from 0 to 30, not a text on how to build, tune, etc.
The ebook for Beginners is once again a FREE download on Amazon for the days April 18-20 inclusive (3 days). I think Amazon goes by Pacific Standard Time (USA), so keep that in mind. It should be available anywhere in the world that Amazon has ebooks for sale. Here is the link - please spread the word. Note that my other ebook is also free for that time period - see the "author" page for that one.
Or, search Amazon for "Quadcopter Book".