Tipped as a future Prime Minister before Margaret Thatcher came to prominence, Barbara Castle is arguably the most prominent women politician in the history of the Labour party.
If politicians are remembered at all, it is often not in the way they might have wished.
Nor is it a static process. Immediate assessments are revised and revised again so that an individual career might seem quite different from one generation to the next, and individual rankings soar and dive.
Barbara Castle who was born 100 years ago on October 6th and who died in 2001, has soared in public opinion ever since she quit politics, propelled on the updraft of anti-new Labour sentiment and continuing frustration at unequal pay.
Barbara was the third and youngest child of Frank Betts, a tax inspector, an occupation which was both safe at a time of terrible economic uncertainty, and relatively well paid.
More importantly, he was an ardent socialist, and an intellectual who taught himself Greek and Icelandic as well as Spanish and Italian well enough to read key texts in the original.
He and his wife Annie believed in socialism not only as a political creed, but as a way of living. Socialism was, of course, about economic redistribution and justice but it was also about giving everyone access to education, music, art and the countryside.
Barbara fought her way into the almost all-male Oxford, and out again, into the largely male world of politics.
She began an affair that lasted until his death in 1942 with an older, married man, William Mellor.
Mellor was a leading figure of the intellectual left and became the founder editor of the left-wing magazine Tribune. He gave her the introduction she craved to the London political world.
Barbara was destined to make a contribution to politics. At first it was as a journalist, but in 1944, after a series of rebuffs, she was selected for Blackburn, the seat she represented from 1945 until she retired - passing her seat on to her special adviser Jack Straw - in 1979.
Barbara, the youngest of the handful of women MPs elected in 1945 was marked out by her slightness and above all by her flaming red hair. Women in public life had to be seen to be respectable. Part of the deal of getting selected was getting married.
She chose the journalist Ted Castle, a man who knew how to capture the public imagination.
Barbara's career began with a double page spread in the Picture Post and in terms of publicity never looked back.
Her personal charms won her admirers: her passionate advocacy of the causes of the left guaranteed her criticism.
The commentators rarely knew which way to turn, particularly when she began to protest angrily at the way detainees accused of supporting the Mau Mau were treated in Kenya, or at the brutality of soldiers supposed to be keeping the peace in Cyprus.
Even so, when in 1964 her closest political ally Harold Wilson became prime minister he put her in his first cabinet as minister for overseas aid.
She was from the start a brilliant minister - a woman with a clear sense of purpose, a genius for attracting public notice to her schemes and enough clout with the prime minister to get her way in interdepartmental disputes.
In 1966, despite being a non-driver and - perhaps worse - a woman, Wilson moved her to the Department of Transport. Her battles with the empires of men began. First it was the breathalyser, and then seatbelts.
She was showered with personal abuse and ridiculed by interviewers - "You're a woman. And you can't even drive" was a typical introductory remark.
By 1968 she had achieved an extraordinary fame that encouraged some observers to prefer her over the iconoclastic Roy Jenkins as the next Labour leader.
Just as the relationship between government and the unions came to breaking point over the link between pay claims and inflation and the value of the pound, Wilson gave her an even bigger job - he asked her to go to a new department of employment and productivity.
Barbara brought the government to the brink of catastrophe by trying to introduce trade union reform against the overwhelming opposition of union-backed MPs led by Jim Callaghan who would later be prime minister.
Her initiative, In Place of Strife was a bold and bonkers miscalculation from which at the time it seemed her reputation would never recover.
But immediately she struck back with the introduction of the Equal Pay Act, the last piece of legislation to reach the statute book before Labour's defeat at the 1970 election.
And she was not finished. Back in government between 1974 to 1976, she radically reformed pensions and brought in child benefit as a payment to mothers rather than through the father's pay packet.
Today, when her attempt at union legislation looks insignificant compared with what was to come, when drink-driving is (nearly) socially unacceptable and safety belts treated as part of the process of starting the car, it is for introducing equal pay that Barbara is most warmly remembered.
For a politician who rejected the segregation of women's issues as a way of diverting attention from socialism, who dreamt of a minimum wage, who fought to outlaw private practice and paybeds from the NHS and campaigned for a genuine global redistribution of wealth, equal pay seemed a relatively minor achievement.
But for all her radicalism she also understood that change usually comes in increments. And even incremental change only happens when there is a radical individual demanding much, much more.