The midlife crisis was first described by a psychoanalyst in 1965. In 2004 economists David Blanchflower and Andrew Oswald found that age was a determinant of happiness: there was a U-shaped relationship between life satisfaction and age, with the bottom of the curve occurring in the early 50s.

In this fascinating and even uplifting book, US journalist Rauch talks to scientists and ordinary people who have experienced the midlife crisis. He prefers to call it the “midlife slump” or even “midlife reboot”, arguing convincingly that it is a normal transition, like adolescence, that leads to a more stable, positive stage of life.

But ageism is widespread and attitudes must change in an ageing society. He challenges negative stereotypes about older workers (they are as productive and as healthy as younger ones) and argues that such prejudices prevent us from coping with midlife and beyond: “Most of what people think they know about happiness and ageing is wrong and is hurting them”. Now in his late 50s, Rauch says that writing this book has made him more optimistic about the future: “Ageing equips us to be happier and kinder.” Old age can be the most satisfying period of life, “a gift the likes of which mankind has never known before”.

• The Happiness Curve: Why Life Gets Better After Midlife is published by Green Tree (£9.99). To order a copy go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £15, online orders only. Phone orders min p&p of £1.99.