When The 100-Year Life first appeared in mid-2016, the book about longevity and societal change sold only modestly in the West. Some took it as an inspiring road map, some as a warning, some as a niche-interest read for human resource departments or pension specialists.

But when the translated version was published in Japan a few months later, it hit the world's most aged nation like a jolt of electricity. To Japan, the book's central thesis - that individuals, institutions, government, finances and infrastructure need urgent preparation for a time when millions can reasonably expect to live for a century - touched the rawest of nerves. It became a huge bestseller, transforming the public debate and crystallising what had been a murky discussion of demography-themed hopes and fears.