In 1961 a Hungarian-born BBC drama producer named Martin Esslin published a book of criticism, and the book invented its own subject. The Theatre of the Absurd gathered Beckett, Ionesco, Genet, Adamov, Pinter — writers who didn't know each other as a movement, several of whom resented being called one — and gave them a name accurate enough to stick. Critics had been calling these plays formless nonsense. Esslin's insistence was quieter: there's a form here, you're reading it with the wrong grammar.
I first read it as a student in Delhi, in a library copy annotated with increasing hostility by previous readers, and used it the way students use criticism — a decoder ring, here's what the tree means, here's your essay. Rereading it this winter, the argument is better than my student self could see. The point was never that these plays are puzzles with bleak solutions. It's that they enact their ideas instead of arguing them. A conventional play might have characters discuss the difficulty of communication, eloquently, and so refute itself. Ionesco just lets language disintegrate on stage in front of you. The form is the argument.
That distinction has followed me well outside theatres. The most honest work in any field demonstrates rather than asserts. I've sat through slide decks insisting an architecture is simple, and a few demos that simply were — the difference in the room is total. Esslin would have recognised the slide decks immediately.
The other thing the book teaches, almost by accident: what generous criticism looks like. Esslin wrote about baffling new work as a believer with a torch, not a judge with a gavel — assumed the strangeness was intentional and asked what it was for. Sixty years later most of the plays he championed are classics, and the book reads like common sense, which is what happens to criticism that succeeds.