Leanpub bookshop: free books - R, statistics, data mining!

I highly recommend https://leanpub.com/

• If you are poor, most books are free of charge. Initial price is a suggestion.
• If you wish to contribute, move the slider to select the contribution. See how much author earns!
• Buy the book when it is developed - author gets encouragement and early income!
• Some books accompany free online courses, eg. coursera.
• Select epub, mobi, pdf....

I selected a book R Programming for Data Science by Roger D. Peng

PS/OT This reminded me about a wonderful book about programming and C# fundamentals: http://www.introprogramming.info/english-intro-csharp-book/ 

Learn R, learn C#, it costs nothing!