This is one of those rare collections of short stories that sticks with you. I read it for the first time a long, long time ago - probably in the early 1970s - and I can still tell you without looking almost half of the stories it contains: Asimov's "The Ugly Little Boy"; Phillip K. Dick's "The Father-Thing"; "Star Bright" (don't remember who wrote it); Jerome Bixby's "It's a Good Life"; Zenna Henderson's "Gilead"; Fritz Leiber's "A Pail of Air"; Ray Bradbury's "All Summer in a Day." All stories I'd read before or since in other places, but stacked up together here, all of those children, gifted, malevolent, frightened, excited - collectively, this is a true heavyweight.
Seems that others believe it, too - you can't even touch a copy in hardcover for under $50 - even Book Club Editions or ex-library copies, which is about all you'll find these days. And I mean even with no dust jacket. If you find one, grab it, and hang onto it - not as an investment, but because it's a damn fine book.