A short book by a serious Big-Thinking author, Francis Fukuyama. His theme is right there in the title: Identity. And he takes us on a magical mystery tour of all its origins and manifestations.
Origin-wise, the Greeks had a word for it: thymos, which they recognized as a separate component of human consciousness, apart from the facilities of reason and desire. It is the demand for recognition of one's dignity by one's fellow people. (Fukuyama quotes Adam Smith, but not the most succinct version that supports his thesis: "Man naturally desires, not only to be loved, but to be lovely; or to be that thing which is the natural and proper object of love.")
Which would be fine, even admirable, if it were limited to what we are entitled to by the bare fact of our species membership. But thymos often comes into conflict with one's social environment, especially when one has an unusual sense of one's nature. It then turns into a game of oppressor (society) vs. the oppressed (me, and people like me).
Even that's not necessarily bad: some people really are oppressed, and thymos can drive them to seek fair redress. More often these days,… well, you can read the papers as well as I can.
Even worse than standard thymos is megalothymia (Fukuyama's own word): the inner need to be recognized as superior to others. This isn't necessarily fatal; some form of megalothymia probably exists at the root of every damned politician, CEO, or movie star. But it's also the underlying motivation of every despot (or psychopathic killer, although Fukuyama doesn't go there).
The discussion is wide-ranging, because once you see the universal trait of thymos, it's not easy to unsee it: you start detecting its influence in every public policy debate. Immigration, education, trade, welfare, … you name it. And Fukuyama notes especially where an overdose of identity has brought us (and others) into a fractious state.
Fukuyama writes from a mildly liberal perspective, which can be a little off-putting at times. He admits that the key impetus to writing the book was Trump's election, and also the Brexit vote. He views both as horrible, and products of megalothymia.
And then sometimes he just goes off the rails. He writes of the Obamacare campaign: "The ACA's opponents tried to frame it as an identity issue, suggesting sotto voce that the policy was designed by a black president to help his black constituents."
As someone who was paying attention to opponents' arguments, I'm reasonably sure that's a lot of hooey. (Although claiming that such framing was "sotto voce" allows Fukuyama to get away with not actually providing examples.)