App Store and Amazon.Com
Basically all of the App Store chess apps are the same. Stockfish is free and perfect. Basically all chess books are good and the amazon.com ratings don't tell you if the book is readable. It's not so easy to find a readable (enjoyable) chess book. The chess audience likes to feel like they are an adult reading a challenging book. Unfortunately, not everyone wants to feel this way (including the adult who "thinks" they enjoy this type of challenge).
