Karl Marx, in one of his occasional puckish moments, said “I am not a Marxist.” Margaret Thatcher never ever said “I am not a Thatcherite”—but more often than not, she was not. That much emerges from this new biography, which is concise but complex, pointed but finely balanced. Other than Queen Victoria, Margaret Hilda Roberts was the only woman in history to give her name to a major ideology, but Thatcherism evolved over time out of changing political conditions. She eventually became “The Iron Lady,” but even then she could be prudently flexible.

This book is dedicated to “Mrs. Thurman,” who (it turns out) was the headmistress of the Birmingham Church of England school that young David Cannadine attended in 1955:

So when the other “Mrs. T.” appeared on the national political scene, Cannadine (and every other Briton who remembered that very common type of headmistress) immediately recognized her.

It is said that she was shaped by her father, Alfred Roberts: a militantly self-reliant and politically independent Methodist shopkeeper. But he represented an England that was already dying, and by 1947, when she graduated from Somerville College, she was evolving. To be sure, she was always a Conservative, but at first her Toryism was fairly liberal, embracing Keynes and Beveridge. (Later she would call this compromise “wet.”) In 1952, she told the Sunday Graphic that women should pursue careers and enter politics and that someday Number 11 Downing Street might have a female occupant. (She said nothing about Number 10.) In 1967, she voted to legalize both homosexuality and abortion. And she protested (with tangible resentment) that male chauvinism would never permit a woman prime minister in her lifetime—a prediction made less than a decade before she won the prize herself. (Throughout her tenure as premier, she and British feminists despised each other, and she almost never appointed women to high office.)

Cannadine's book is essentially the entry on Thatcher that he wrote for the Oxford Dictionary of National Biography, in hardcovers. He therefore had to strive relentlessly for two goals: fair-mindedness and brevity. The first he achieves fully, at a time when Thatcher is still revered by American conservatives and reviled by British academics. But compressing such a multifaceted political actor into such a short space is far more challenging, perhaps impossible. Some episodes are inevitably simplified, notably her first big political firestorm. Everyone knows that as education secretary she cut back free school milk and was forever branded “Thatcher—milk-snatcher!” But it needs to be explained that by the 1970s children considered school milk uncool, that most of it went to waste, and that Thatcher very sensibly reinvested the savings in new school construction. She also expanded preschool and higher education, greatly increased overall education spending, hired more teachers, shrank class size, and rescued the Open University when other Tories wanted to strangle it in its crib.

Here again, Thatcher was not a Thatcherite, at least not until the mid-1970s. By then, she had been driven to the right by Edward Heath's failures and u-turns, as well as the influence of Keith Joseph, Milton Friedman, F. A. Hayek, and monetarist think tanks. At the time, most Tory MPs did not realize how far her views had shifted. And so they elected the first female leader of the Conservative Party in a fit of absence of mind, mainly (Cannadine concludes) “because she was not Heath” (21). Many of those same MPs, “drawn from the male worlds of public schools, regiments, professions, boardrooms, and clubs, soon began to wonder what they had been doing when they voted for her” (24).

In her successful 1979 election manifesto, there was much about cutting taxes and controlling the money supply, but practically nothing about privatization or curbing the trade unions. Her first cabinet consisted mostly of Heath men, so she could only ram through her controversial programs by bypassing, firing, or “handbagging” them. And after eleven years of systematically alienating the Tory establishment, she paid the ultimate and inevitable price.

The Iron Lady survived as long as she did largely because she knew when to bend to reality. However reluctantly, she agreed to transition Rhodesia to majority rule. Even after the Irish Republican Army very nearly assassinated her, she ratified the Anglo-Irish Agreement. She knew she could not fight for Hong Kong as she had fought for the Falklands. Having lost the inner cities in the 1987 election, she directed £3 billion in aid to those areas. But conversely, when she was a rigid Thatcherite, she often steered firmly towards disaster. Her resistance to sanctions against South Africa left Britain diplomatically isolated in a morally untenable position. And her insistence on the poll tax was pure and simple political suicide.

Sharply written and compact, this volume would be ideal for classroom use, explaining not only Margaret Thatcher but also the world she worked in and helped to transform. Today, when another generation of strong-headed, disruptive politicians are taking on establishments and polarizing public opinion, your students might be fascinated to learn about a larger-than-life populist prime minister. As Cannadine sums her up, “She wanted to make Britain great again” (34).