I haven't read it yet, but reading it is not going to change your personality. Personality defines how you receive it.
If you change your entire personality based on a self-help book.. that probably says a lot about your personality.
And anyway twin studies make the hardware seem more impactful than the software in many ways..
Personality is not a static entity. It’s a feedback loop, a conversation you can have with yourself to adjust over time. My brother had intense anxiety in cars. He applied techniques that improved his ability to handle the situation. Saying he has an anxious personality is ultimately defeatist and not reflective of the agency we each possess.
And twin studies, while persuasive that biology does have a massive impact are not dispositive compared to similar studies on human development theory that has longer population sizes that show self dialogue can shape behavior over time.