Being a particular type of personality is much more important than reading books on trading methods. You can master trading without reading a single book but you'd be lucky to survive a few months if you aren't the right personality.
you seem to imply that textbooks written by experts are useful. i think that’s meaningless. usefulness of the message conveyed by the expert depends on the person interpreting it. statements like that should always include ‘to me’ as in ‘to me textbooks written by experts were useful’. the same textbooks could have been totally disastrous in consequences to others.