One reader challenged me to a test: make one book available both on paper and as an unprotected PDF file. Report the effect of sales after one year. I did that. The results were clear: Piracy was rampant. The book was everywhere online. But weirdly, my readers were also proved right. Sales of the printed edition did not suffer; in fact, they rose slightly year over year.

A recent satirical children’s book showed how piracy can actually boost sales. Months before the book came out, a PDF of the story was leaked online and promptly went viral. Yet the leak generated so much interest in the book that eager readers soon pushed it to the top of Amazon’s best-seller list.