The "Most Expensive" trading book is the one that draws a trader in and makes a cause for possibilities. Then the trader goes along with those possibilities and after some time of working with those possibilities the trader realizes that the author was full of BS. Then the trader has to unlearn those bad ideas and learn the correct ones. Thus that book costs money but more importantly damages the trader's mental state and wastes the traders time.
Amen to that. There comes a point at which you (the reader), will stop and say, "but hey, I tried what he said on a different chart and for some reason it doesn't do what the examples he shows says it's supposed to." Even though the author is conveniently not present to assuage your uncomfortable feelings, you will hopefully discover over time what "cherry picking" means. That is the critical point where the real learning begins.