I'm the author of this book, Karan Dwivedi, ( alias programmergamer and karan1337 here) all those mails and contact methods listed in the end are my contacts. There is no need of a licence,its totally free, U CAN COPY AND DISTRIBUTE THE EBOOK AS MUCH AS U WANT. BUT U CANNOT EDIT IT!
Sorry, i forgot to include in the posts i made all over the internet that the ebook is free, will make the appropriate changes as soon as possible.
Comments to be posted on my blog for ease of all- http://programmergamer.blogspot.com
under the post "My First Ebook!" Also u can follow me on twitter for latest updates and events.