I'm not sure if he's thought of as experimental these days, but I am sure his crazy-funny speculative imagination, brutal political satire, acidic existential irony, poignantly unfussy prose, and liberating structural waywardness lured a host of my generation during our teens onto the wilder side of fiction, into narrative irreverence and opportunity.
I'm also sure I consider Slaughter-House Five (1969) one of the best novels about World War Two, not to mention one of the best of the second half of the twentieth century. By way of a eulogy, let me simply quote a passage from it. Billy Pilgrim has just been snatched by extraterrestrials called Tralfamadorians who intend to put in a kind of cage in a kind of zoo on their planet.
There were two peepholes inside the airlock [of their spaceship]—with yellow eyes pressed to them. There was a speaker on the wall. The Tralfamadorians had no voice boxes. They communicated telepathically. They were able to talk to Billy by means of a computer and a sort of electric organ which made every Earthling speech sound.
"Welcome aboard, Mr. Pilgrim," said the loudspeaker. "Any questions?"
Billy licked his lips, thought a while, inquired at last: "Why me?"
"That is a very Earthling question to ask, Mr. Pilgrim. Why you? Why us for that matter? Why anything? Because the moment simply is. Have you ever seen bugs trapped in amber?"
"Yes." Billy, in fact, had a paperweight in his office which was a blob of polished amber with three ladybugs embedded in it.
"Well, here we are, Mr. Pilgrim, trapped in the amber of this moment. There is no why."
Goodbye, Kurt. There are a lot of earthlings still unstuck in time who will miss you.