Books are Simplified Version of Reality

Reading books is reading filtered and structured knowledge. Compare to other sources like news, articles, forums, it has relatively the highest signal to noise ratio. That value comes with a cost, most notably generalization and omission of some details and context-related materials. Relative to other more "real-time" sources it is more "sterile".

This is why when we read books we feel we got so much information but sometime we are left hanging when trying to implement it in our situation. It's because the details in books are already smoothen out, some parts are simplified, so it is up to the reader to put them back on the reality ground. If I am going to write about some new techniques I would not have enough space to cover all possible cases but only take that I think would be enough to inspire and make a point to the reader.

There's nothing wrong with it, of course. It's just how the books are positioned and made. It's the forums, mailing lists, discussion group and our own experience role to fill in the blank. Besides, it's where the fun lies anyway.