No matter how careful the authors are, even if multiple people review the manuscript before publishing, humans make mistakes. Paper books cannot be corrected immediately, so authors publish the errata sheet and show what should be corrected. Usually, there is an official page about the book on the publisher's website, and there should be errata in it. Books without errata are perfect from the beginning, or the authors do not intend to improve the book. I think the possibility of the former is very low.