WooHoo! It has been such a long road to get this book published. I wrote a bit about it here. It is finally officially available on the Packt site for sale today! It should be available on the Amazon store by Monday the 1st of February. I will have a list of additional sites and urls later this week. If you want the best book on NativeScript (I know I'm so funny! I get to claim it because its the only book on NativeScript!) then it is now available!
The available sites are as follows: