At his blog, Mark Batterson offers a perspective that authors and publishers should thing about more seriously. It begins:
Here is a lesson I learned when I wrote In a Pit with a Lion on a Snowy Day: if your book is worth reading then you can't give away too many copies! On one level, every book given away subtracts from sales. But on a much higher plane, every book given away multiplies sales. I've chosen to take a multiplication mindset. Here's my rationale. If people like the book, they will buy a copy for someone or tell someone about it. First generation readers spawn second generation readers via word of mouth.