At 54, the married father of three has snorted small amounts of heroin for as many as 10 days in a row and enjoyed it mightily – even if, as he recalls in his new book “Drug Use for Grown-ups: Chasing Liberty in the Land of Fear” (Penguin Press), he’s experienced mild withdrawal symptoms “12 to 16 hours after the last dose.”

But, as Hart sees it, the discomfort is a worthwhile trade-off.

“There aren’t many things in life that I enjoy more than a few lines by the fireplace at the end of the day,” he writes, pointing out that the experience leaves him “refreshed” and “prepared to face another day.”

Hart, who studies the effects of psychoactive drugs on humans, finds his use of the narcotic to be “as rational as my alcohol use. Like vacation, sex and the arts, heroin is one of the tools that I use to maintain my work-life balance.”