Note my words "perhaps".....
There is fair use, no question...and trust me, I shudder to think of the world where someone can't walk down the street and safely whistle a Beatles tune (wait...I hate Beatles music...the whistler should be clubbed....bad example)....but even certain specialized books have licensing agreements.
Keep in mind something - the more "passing around", the more potential for abuse
I'm not chastising Mike (well, not on this one, anyway), but the truth is that most books have enough spoiler/teaser info available online to entice people to buy.
For the book I wrote and the one I contributed to, I'd object to what Mike is describing, and I know for a fact that one of the publishers I worked with would not support this either - most publishers run plenty of programs (free individual chapters, sample sections, etc.). . Trust me (as I'm sure you know) a published book represents a considerable investment of time and $$$.
Appreciate your input, but it does not vitiate my original point.