Docker itself is an awesome piece of technology. But something I always wonder about books which are covering a technology which can (and does) change over tim

Docker itself is an awesome piece of technology. But something I always wonder about books which are covering a technology which can (and does) change over time, how current the author is determined to keep the book current (let it be with a new edition every few...). And why needs to be this zero-hero thing? Is that really something people look for? :D