Mastering Bitcoin, by Andreas M. Antonopoulos
[WARNING: Did you catch the "milk sad" incident a few months ago in which funds were lost due to people using the default 'bx seed' command to generate a bitcoin address? The default invocation of this command appears in the second edition of this book without any warning or disclaimer about its unsuitability for use with real funds! Always know the entropy source when generating seeds/keys for production use!]