IMO, your book is far too expensive. As a casual interested in dev-ops (surely your target market), I'm completely turned off by you asking old-academia style prices of an ebook. I appreciate you're charging to cover the opportunity cost of your consulting, but presumably you're also aware that pricing it on your perceived value is a suboptimal strategy. Have you considered reducing the price to open up a larger market, and if you have, what is your justification for not doing so?