An NPD abuse survivor himself, Ross is a psychotherapist specialising in NPD, has written several books on the subject and has an excellent YouTube channel on the subject. Great general information on Narcissistic Personality Disorder, what causes it, how it manifests itself, what (if anything) can be done about it.
He is knowledgable about his topic and presents it well to the layman of intellect.
Crucial background introduction to Narcissism
The Frightening Truth: Pathological Narcissists Groom Victims Like Child Molesting Pedophiles
Covert Narcissists – The Wolf in Sheep’s Clothing
Gaslighting – that subtle a practical guide