Her claim to fame
Object of desire in her student days at Oxford: no shortage of male volunteers to carry her books; education secretary in Jim Callaghan's Labour administration; destroyer of grammar schools doing "more damage to this country than Hitler", according to the late Auberon Waugh.
In 1974 she was nominated by Time magazine as likely to be Britain's first woman prime minister; in 1981 she resigned from the Labour party with the "gang of four" who founded the Social Democratic party.
So was she the Left's answer to Margaret Thatcher?
Not likely. Apparently a stranger to the hairdresser, she gave the women columnists a field day. "SW always looks like she's left the stove on at home," said Lynda Lee-Potter, of the Daily Mail.
Why did she resign?
"The party I loved and worked for over so many years no longer exists." She was disillusioned by the antics of the militant Left, as were Roy Jenkins, David Owen and Bill Rodgers, the rest of her gang.
Did she upset some fans?
Not half: she was Cherie Booth's great political hero. The future PM's wife was so outraged at her defection that she applied to stand as Labour candiate in her home town of Crosby when SW stood for the SDP, but was turned down.
What did the SDP achieve?
Anthony Howard said: "All it achieved was to see to it that the Tories would be able to ride roughshod over the divided forces of the Centre and the Left in the three general elections which followed."
But Polly Toynbee claims that Tony Blair is a "fully baptised social democrat".
Does she like New Labour?
Paddy Ashdown, in a 1996 entry to his diary, said: "She doesn't have a very high opinion of Blair; she thinks he is a fixer and she doesn't know what he stands for."
What is she doing now?
Hitting the campaign trail with Charles Kennedy et al. As Matthew Parris said in The Times: "SW is the cherry on the sundae of any gathering of the nice and the good."
Born: July 27, 1930
Education: In UK and US; Somerville College, Oxford; Columbia Univ, New York
1952-58: Journalist on the Daily Mirror and FT
1964-79: Labour MP, Hitchin, then Hertford and Stevenage
1967-69: Minister of State, Department of Education and Science
1976-79: Secretary of State, Education and Science
1981: founder member of the SDP
1988-: Professor of elective politics, Harvard University
1993: Life peer