No wonder so many boys are so miserable. The modern world of extended years in school and delayed adulthood cuts them off from what they need most. As Adam Cox, a clinical psychologist who interviewed hundreds of boys across the English-speaking world, writes: “The primary missing ingredient in [their] lives – the opportunity that separates them from a sense of personal accomplishment, maturity, and resilience – is purposeful work.”

Boys long to be part of something bigger than themselves. And the bigger and more challenging the task, the happier they are. “If you tell 10 boys you need volunteers to go downtown and work all night on a big, dirty, tough job, and you still expect them to show up at school the next day, they’ll all jump up and volunteer,” says Ms. Gauthier.

Boys also need to imagine themselves in heroic situations. When girls are asked about Vimy Ridge, they say, “Whew, it must have been horrific.” When boys are asked, they imagine what they would have done if they’d been there. “Our most powerful assembly is on Remembrance Day,” says Mr. Power. “Every boy is thinking to himself: How would I have measured up?”