[kotutku]

The author usually gets <5% share from the book price. I guess it's much better (although not legal) to just skip buying the book and send a donation directly to the author.

[kwhitefoot]

Not all authors will accept such donations because it puts them in competition with their publisher.

See Charles Stross: https://www.antipope.org/charlie/blog-static/2009/03/reminde...

[panzagl]

They also acknowledge that many people work on a book besides the author.