The president doesn’t exactly have a sterling reputation for discretion, but if there’s one area where he exhibits a remarkable, vault-like secrecy, it’s the substance of his own finances. Repeatedly saying he’s “really rich” is one thing; actually proving it is another. The gilded atrium of Trump Tower on Fifth Avenue symbolises the opulence and glamour that President Trump has always wanted to project, but as the Forbes reporter Dan Alexander suggests in his new book, White House, Inc., more telling might be the 43rd floor of a “forgettable” office building in San Francisco. There, Mr Alexander found a reception