Students of Robert Caro know of a particularly famous trope of his: In order to write a book, he must first know its final line. Deep into his reporting of The Power Broker, he tells me, “I couldn’t figure out how to write it. It was just such a mass of stuff, and I couldn’t see how it all tied together.” He was, he says, “in a sort of mood of despair.”

Then on June 3, 1967, he attended a dedication ceremony for a park at the site of the 1964 World’s Fair. Moses’ power was waning by then, but the front two rows were stacked with his old-guard loyalists. “All his engineers and architects,” Caro says. “You know, the ‘Moses Men.’ What I remember was they all had gray heads.” Moses alluded to the public’s ingratitude to great men. “And I remember them nodding,” Caro says. Afterward, the men walked past Caro, and he could hear them talking, saying that Moses was right and wondering why people didn’t appreciate what Moses had done. And a phrase stuck in Caro’s head that summed it all up: Why weren’t they grateful?

In that instant, Caro says, everything became clear. “When I heard that line, I said, ‘Oh, that’s what this book is about,’” he recalls. And he didn’t just know how the book would end—with a description of that day’s event, ending with those four words. He could see—“in a flash,” he says—how everything he had learned and everything he was still to write would lead to that point. “I knew in that moment how to do the book. And I remember going back to my office and writing an outline as fast as I could. I was abbreviating words because I wanted to get all the words in there.”

With each subsequent book, Caro has needed to know where he would end before he could launch into writing it. “I mean, everybody has their own way of writing,” he says. He is careful to clarify that knowing a final line isn’t some kind of glib talisman. “Somehow that ending tells you what’s important in everything that’s come before it, even if it’s 1,000 pages that came before it.” He goes on, “Once you have it, everything becomes easy for me.”

The moment he says this, his chosen adjective—“easy”—hangs in the air between us. The first volume of The Years of Lyndon Johnson, The Path to Power, which is about Johnson’s early life leading up to his first failed campaign for public office, took seven years. The second, Means of Ascent, detailing Johnson’s eventual election to the Senate (an election that Caro’s groundbreaking research definitively established was stolen), arrived eight years later. The third, Master of the Senate, about Johnson’s years as Senate majority leader, came 12 years after that. Then another ten years passed before the publication of The Passage of Power, which ends in 1964 after Johnson has assumed the presidency following John F. Kennedy’s assassination. That book was published nearly 13 years ago.

“Easy,” I point out, doesn’t feel like a sufficient adjective.

For the Conservative establishment, taking on the unions was madness. Harold Wilson and Ted Heath both suffered deep political wounds for trying just that. In their minds unions were unstoppable. Party Chairman Peter Thorneycroft was so distressed by what he saw as dangerous nonsense that he wanted every copy of Stepping Stones burned. Thatcher, Joseph, and crucially William Whitelaw, thought it brilliant, however, and it was integrated into Conservative policymaking. Resistance to these ideas from the Tory machinery remained strong, and progress in articulating policies was limited. When the crucial political moment came, though, Stepping Stones served to focus and clarify the Tories response.

The rise of Thatcherism must be grounded in the context of the seventies. The long-term record of poor economic performance, the period of relative decline, Britain as the sick man of Europe, undercut support for the status quo. The maladies that produced that decline were masked during the long postwar boom. When global economic crisis emerged, all these problems were exposed, and hence the country lurched from crisis to crisis. A miners’ strike in 1972 saw the lights going out and industry put on a three-day week — before the government capitulated. Another miners’ strike two years later saw more blackouts, more three-day weeks, and finally a gambit by Heath — the snap “Who governs Britain?” election, which he promptly lost. Yet Labour fared no better. Their Social Contract promised industrial peace in exchange for increases in spending, which was pushed to its postwar peak. However, so was inflation, hitting 25 per cent in 1975. A financing crisis followed, necessitating a loan from the IMF in 1976. Labour, now led by Jim Callaghan, was forced into deep spending cuts.

Inflation had fallen yet remained in the teens. Tightening the monetary supply to bring prices down was seen as an unacceptable threat to full employment, so Callaghan opted for an incomes policy, cajoling workers into capping wage growth at 5 per cent. With inflation over 10 per cent, this produced real declines in purchasing power. After two years of grudging cooperation, workers rebelled. The result was the Winter of Discontent, the wave of strikes sweeping the country in 1978-79. Strike followed upon strike throughout a frigid winter, the inconveniences, disruptions, and misery piling up upon the public. As those strikes were settled with increases well above 5 per cent, Callaghan’s economic policy was in tatters, and Labour’s electoral fortunes decimated for a generation.

The calamities of the decade provided political conditions amenable to transformative politics. Having the hardline approach to the unions advanced in Stepping Stones at hand proved most useful. Without it, the Tory Shadow Cabinet would likely have argued in circles over the appropriate response, as that is what they had done for the previous four years.