Back to the Future, again--in a book

Jeanetta reading in Edmond

Standing in Best of Books in Edmond, listening to friend Jeanetta Calhoun Mish read from her book "Okiehomeland" last week, a paperback caught my eye, rousing memories.
"Childhood's End," by Arthur C. Clark, written in 1953, in a new edition. I had to buy it, because I vaguely remember reading it as either a preteen, or teen, and it's been a while since I read science fiction.

Original cover, better than now

I finished it off this weekend, book number two of the year.
Clarke is famous for have introduced the idea of satellites to the world back in the late 40s. So besides a fiction writer, probably best known today for the movie 2001, A Space Odyssey, he was also a futurist with remarkable vision.
As I'm rereading the book about humans' first contact with aliens (hint, it doesn't turn out well), he predicted two other inventions, years ahead of time in 1953--the birth control pill and DNA testing.
What I remember from the book so long ago, and I forgot the source till now, has to do with bull fighting.
The aliens outlaw any killing of animals, which humans ignore. Then one day at a bull fight, a matador jabs a lance in the back of a bull, and the whole crowd screams in agony. End of cruelty. Pretty cool, huh?
I thought so so many years ago, and traveled back to the future this week in a book that includes time travel, relatively--that's a pun and clue--figure it out.