The idea behind the book is so simple it's a surprise it has not been done earlier. The end of the war was a watershed for much of the world and a convenient place to unfurl a contemporary history. Aware that similar accounts have been top sellers in Britain and Europe, Auckland University Press publisher Sam Elworthy asked historians Carlyon and Morrow to fill the gap here.
They have responded with an account which neatly divides seven post-war decades into three distinct periods - the immediate years after the war, dominated by a yearning for physical and economic security, the heady '60s, when the stultifying cloak of conformity was shed, and the tumultuous years after 1984, when first Labour and then National Cabinets unleashed reforms which carried a small South Pacific nation way beyond its familiar comfort zone.
"We are writing about the baby-boomer years," Carlyon said. "A lot of New Zealanders have lived through these years. They will recognise the signposts."
The subject matter and scope is a departure for the authors, whose past two joint works have been well-received suburban histories - one centred on Remuera, the other on Ponsonby. But there are some common threads with the large-scale project, especially in their treatment of the creative, cultural and social fabric.
History in the hands of the Auckland authors is Peter Fraser and Aunt Daisy, Selwyn Toogood and Selwyn Muru, Colin McCahon and Colin Moyle, Bastion Pt and Think Big. It is the Polynesian Panthers and Pat Bartlett, Jonah Lomu and John Minto, the Topp Twins, Truth, Hone Tuwhare and Keith Holyoake. Architects and artists jostle with police and priests, politicians and policymakers, protesters and poets. They write of ferment and feminism, pioneering law reforms, painful schisms and the legacy of neoliberalism.
Says Morrow: "We couldn't do original interviews and our time was limited. We looked at the secondary literature and tried to incorporate as many people as we could so readers could sense the voices from the time, to hear New Zealanders living through episodes in our history."
They divvied up the chapters, with Morrow, who has worked for the Waitangi Tribunal, preparing material on race relations, Treaty issues and Maori New Zealand, while Carlyon tackled research on the economy. Throughout the 520-page book the dominant theme is one of transformation built on foundations of continuity.
Carlyon: "Clearly the economy today bears little resemblance to the economy of 1945. But in some ways there are similarities. We remain dependent on primary exports. Where we once had wool and meat we have dairying and the other products from the land."
And where New Zealand once counted 70 million sheep (and, famously, three million people), modern farmers earned a lot more from a much smaller flock.
Social scientist Leslie Lipson, were he still alive, might have been struck by the scope of change. Made head of Victoria University's political studies department at 27, he published the book The Politics of Equality in 1948, portraying a country where a fierce levelling worked to create a sense of bland conformity. Carlyon thinks Lipson, who died in 2000, would be "blown away" by contemporary New Zealand. "He'd struggle to recognise the place."
Canadian Morrow, who came to New Zealand in 1980, experienced the same feeling when she settled in Wellington. "Every cafe was the same," she recalled.
Then, bang! Sir Robert Muldoon was thrown out, David Lange and Roger Douglas let the genie out of the bottle and Kiwis suddenly had the freedom to succeed - or fail.
In a chapter titled "A plaited rope" - a reference to building a nation by weaving its diverse peoples - the authors survey the strains from increasingly blended cultures and ethnicities, as the country absorbed waves of Asian migrants. Barely two generations ago New Zealand was "statist, conservative, proudly monocultural," they write.
Today it is one of the most diverse societies in the OECD, with more than 200 ethnicities.
Both writers say they were frequently surprised as they revisited the dramatic changes of the past three decades. "It was a bit frightening," said Morrow, "going back and discovering how much we'd lived through but hadn't realised at the time."
It was clear, they say, that their broad sweep illustrated how rapidly New Zealand had become a less equal country. They write: "New Zealand has become a more socially divided country with greater extremes of poverty and wealth. As individualism has grown so too has conflict, division, and social and economic inequality."
An "earthly paradise" has given way to uncharted waters.