I'm reeling from all the second-wave hate.
I'm not, alas, the well-read one

but by my understanding the 2nd wave begins with Simone de Beauvoir in the late 1940s: the differentiation between sex and gender, and the beginnings of a theory of patriarchy (why men, as a group, dominate and oppress women, as a group). Then a gradual rumble until Betty Friedan's
The feminine mystique (1963) which debunked the myth that Betty Draper-type women got fulfilment from housework and wifeliness. Grassroots organisation picked up with the civil rights movements and included:
— successful campaigns for the rights to abortion, divorce and inheritance, and the final scrapping of the idea that a married woman was legally the property of her husband;
— "the personal is political": raising awareness of domestic violence, rape and sexual abuse, opening shelters for survivors, and 'no means no';
— employment legislation governing equal pay, harassment, and sexual discrimination;
— legal recognition of female homosexuality (which had been sort of invisible in the UK until 1967) and challenges to obscenity laws which made it an offence for same-sex couples to, eg, kiss in public;
— the creation of women's liberation movements, the first diversity and equal opportunity groups in corporations and public institutions (sorry Mr Littledick), and in the US the National Organisation for Women.
In universities, women's studies emerged, the canon of 'dead white males' was challenged as storygirl says, institutional inequalities and discrimination were contested, and feminism spread from being polite, straight-laced and ivory towerish into communes, direct action, organised protest, revolutionary manifestos (notably SCUM and Valerie Solanos — her what shot Andy Warhol), separatist wimmins' republics and 'political lesbianism', a temporary rejection of heterosexuality among (a very small number of) straight women.
The dominant theories of second wave feminism — and they were multiple, and fast-changing — were essentialist and often took as their starting point, when analysing inequality, the body. An example of this is
The female eunuch by Germaine Greer, which locates the source of women's oppression in the biological difference which reduces women to their reproductive function. This now seems misguided, but back in the 1960s the main obstacles faced by middle-class women such as Greer and Gloria Steinem did appear to be based on biology: no access to abortion, motherhood as destiny, abnegation of female sexual desire. Unfortunately, pursuing this biologically essentialist argument led some thinkers, including Greer, to deny that transwomen were women. It should be noted that many second-wave feminists have reconsidered their position on transpeople in the context of queer theory, and a few, eg Twisty Faster, were never trans-phobic to begin with. I know a couple of radical feminists who identify as lesbian transmen: it's more complex than 'radfems = trans-phobes', I think. (I hope.)
Towards the end of the second wave, as feminism became more ambitious and the theories behind it more revolutionary, and in the face of a backlash from men, from the media and from all sorts of women who did not feel represented or included by the movement, an extremist tendency developed. It was never very large, but it did attract attention. It was quite varied, but generally critical of heterosexuality, which was felt to be the reason why ordinary women had not joined the revolution. A lot of radical theory is
interesting: Catherine MacKinnon's criticism of pornography, Andrea Dworkin's attacks on prostitution, and Sheila Jeffreys' dismissal of the very notion of heterosexuality are all compelling and, I think, deserve to be read — critically. I'm not sure their ideas are all wrong, but some of them clearly don't stand up to scrutiny (I mean, heterosexuality
does exist, surely), and ultimately the main problem is that they're a dead end. Perhaps all sex between men and women
is infused with unequal power relations and misogyny. Logically, that means feminists should abstain from sex with men. Well, why should they? And, frankly, who's going to?
In summary, I think 2nd wave feminists did a lot of good and a bit of harm. If I had to identify with a wave myself, it would be 3rd, but when Naomi Wolf and company start burbling about eyeliner, I admit I have a wee yearning for the 2nd.