What do we tell our boys about what it is to be a man? Often, the answer is a long list of toxic traits. We should not be surprised by the results.

A constant, pervasive drumbeat tells boys and young men that certain behaviours and attitudes are inherently male. The bleak outcomes facing today's young men - in suicide, addiction, joblessness, academic failure and radicalisation - are the predictable consequence of a culture comfortable with these crass generalisations.

The answer is not, as the manosphere would have boys believe, to blame feminism. It is to learn from it. Feminism gave women clearly defined and fiercely defended rules for what a woman is not. We need the same for men.

What a Man Is Not sets out a vision of masculinity that rejects bleak and toxic worldviews. It makes a passionate case for the boys we are losing - and offers a practical, optimistic plan for getting them back.