I'd seen the first book around the second-hand shops for some years, but nothing about the blurb grabbed me. Another "series writer," so what.
And I didn't make the connection with a series of other books he wrote: Leah, Rachel, and others.
But I read some online comics, and apparently Card stirred up a huge furor: the word betrayal turned up frequently. Hmm? The complaints boiled down to "He wrote so movingly of acceptance and understanding of even the most outcast, and then he wrote this."
That told me a few things: Apparently I'd missed out on a very well-respected as well as popular author, and apparently he was a deep enough writer to understand both toleration (mercy) and judgement, which LeGuin, for all her skill, is not.
The library kept Ender's Game in the Young Adult section; which made it a bit hard to find at first. (I don't understand at all how they decide what goes in that category.)
The thesis of Ender's Game is that an alien insectoid species (Buggers) have twice attacked Earth, which has, under a compromise government, mobilized a space force to defend humanity. The children with the most promising sets of skills and psychological profile (as tested, anyway) are taken to a space station to Battle School. There, though they have ordinary courses, they learn leadership and innovation through (safe) combat games.
Ender is a (rare) third child. Both his older brother and sister were tested and rejected--the brother too vicious, the sister too mild--but all are off-the-charts brilliant. Little, and often a target, Ender goes to Battle School, where he shines despite the harsh treatment and crushing pressure--external and internal.
That much doesn't give anything away. The story is not suspenseful in the sense that there's any doubt who will be the commander--the title tells you that already. But it is a good story about how to try to train someone to be empathic enough to be a good leader, empathic enough to figure out and respond to an alien enemy's strategy, and ruthless enough to destroy and to spend your own men to destroy.
So I picked up Ender's Shadow, a "parallel" book written much later, and from the point of view of Bean, an even younger and brighter child than Ender. Not quite as moving, but well done, and obviously designed as part of a series (which, lo and behold, it is).
Tastes will vary, but I recommend the book.