One of the astonishing takeaways I am gleaning from Mary Trump’s book about Uncle Donald — the current president of the United States — has to do with how those closest to him think of his ability, his credibility, his qualifications.

They think very little of any of it, according to Mary Trump, author of “Too Much and Never Enough: How My Family Created the World’s Most Dangerous Man,”

She recounts, or so I understand, how his sister thought so little of him when he announced his presidential campaign in June 2015 that she thought he was joking. She presumed he was pulling off a publicity stunt to call attention to his “brand.”

Others in his family — sis, a brother and several other nieces and nephews — dismissed his boasting for what it was, empty rhetoric. He wasn’t self-made, as he claimed; he didn’t attend church, yet evangelicals flocked to his side; he is a man of zero principle.

Trump doesn’t apologize for anything. He never admits he is wrong. He tramples over everyone he meets. Trump is callous, callow and without any redeeming personal quality, or so Trump is reporting.

I happen to believe what she has written. What astounds me, though, is how those close to Donald Trump think so much less of him than those who have glommed onto his cult of personality.