ike America, Trump claims to be unique, exceptional, a shining self-creation. This book by his estranged niece demolishes that myth. Mary Trump’s ruthless memoir blames their family for creating him: she sees it as her patriotic mission to “take Donald down”, and she does so by showing how derivative and dependent the ultimate self-made man has always been. Trump was bankrolled at first by an indulgent father, who paid him to be an idle show-off and proudly collected grubby tabloid reports on his antics; nowadays he is propped up by tougher, cannier men such as Vladimir Putin and Senator Mitch McConnell, for whom he is an easily manipulated stooge. Sleaze and graft, we here discover, are Trump’s genetic heritage. His grandfather slunk out of Germany to avoid military service and made a fortune from brothels in Canada. His father was a landlord who passed himself off as a property developer to rake in government subsidies for schemes that were never built. His mother, born to penury in Scotland, remained so meanly thrifty that every week she dressed up in her fur stole and drove her pink Cadillac around the New York suburbs to collect small change from the coin-operated laundry rooms in buildings the family owned; her piggy banks were empty tin cans that once contained lard. She remained emotionally absent, preoccupied by her ailments, while her husband viewed their male offspring as mere off-prints of himself, begotten to ensure that the family kept a grip on its spoils. Raised in such an environment, how could Donald Trump not emerge as “a petty, pathetic little man”? Never having received affection, he bestows it on himself in orgies of preening and boasting; the life partners he serially selects seem to have been chosen from a mail-order catalogue. His first wife, Ivana, is summed up by Mary as “all flash, arrogance and spite”, with a telling “penchant for regifting”. Ivana’s ritualised gift-giving is portrayed as an exercise in contempt: one Christmas she presents Mary’s mother with a luxurious handbag containing a used Kleenex. Melania is a trophy, destined to occupy a glazed niche in a display case. Presiding over a Father’s Day meal at Trump Tower, she utters just one word all evening. That word, expressing at best a theoretical curiosity about the world, is: “Really?” Throughout the book, Mary’s uncle is not President Trump but simply Donald. With casual disrespect, she even deprives him of the definite article deployed by Ivana who always referred to him as “the Donald”. Mary’s professional credentials as a psychologist entitle her to briskly check off what she calls Donald’s “pathologies”, which include narcissism, sociopathy and learning disabilities that may be due to the dozen Diet Cokes he daily siphons into himself. In a startling final condemnation, she charges that his “craven need for ‘revenge’” on opponents makes him, in his nonchalance about coronavirus in New York, responsible for what she calls “mass murder”. Erotomania can be added to the list of his vices. Once at the Mar-a-Lago pool, Donald disgusted Mary by sizing up her breasts: “Holy shit,” he remarked, “you’re stacked.” This wicked uncle is all slavering id, with no superego to restrain the fingers that itch to tweet, to toy with a big red nuclear button, or to “grab ’em by the pussy”. I suppose we shouldn’t make snobbish fun of Donald’s verbal lapses, but it’s enjoyable to hear him commission the architect Philip Johnson to design a “porta-co-share” for an Atlantic City clip joint. He meant, Mary explains, “a porte-cochère, basically a large carport”. Whenever Donald attempted to manage an actual business – an airline, casino or dodgy university – the result was bankruptcy. The lies he compulsively tells are for Mary another “mode of self-aggrandisement”, a cover for his quaking inadequacy. Sadly dim-witted, he even had to hire a surrogate to take the entrance exams for college on his behalf. All his life he has “failed upwards”; he relies on being “rewarded for bad behaviour”, which happened again when the Senate blocked his impeachment. As viewed by Mary, he is an undeveloped human being, who instantly passed from whiny infancy to doddery old age, missing out the intermediate age of reason and responsibility where the rest of us spend time. Nations mistakenly see themselves as clans, rather than amalgams of individuals bound by a social contract. The US began by denying tribalism: its founding assertion was made by “we the people”, whose equality overrode disparities of origin or social standing. But the country has lost touch with its early ideals, and Mary rightly accuses Donald of wanting to remake it as “a macro version of my malignantly dysfunctional family”, with America’s innate optimism warped into a cult of “toxic positivity”. Nor will Donald’s expected drubbing in November put an end to the menace. He has already Xeroxed a zero-talented diminutive of himself in the form of Donald Trump Jr, the cousin whom Mary, with a curled lip, patronises as “Donny”. Her narrative begins in 2017 at the White House, with Donny toasting Donald at a birthday party for his two elderly aunts. Ignoring the guests of honour, the heir apparent instead congratulated voters who “saw what a great family this is, and connected with our values”. Hearing that, Mary begged a waiter to refill her wine glass. In view of the outrages and abuses that lay ahead, she should have asked him to leave her the bottle. • Too Much and Never Enough: How My Family Created the World’s Most Dangerous Man by Mary L Trump is published by Simon & Schuster (£20). To order a copy go to guardianbookshop.com. Free UK p&p over £15