Inherit the Wind by Jerome Lawrence and Robert E. Lee:  Good, good read and a reminder that there are still those who do not believe what science has taught us but thank heaven not as strongly as this tale reminds us.  For those who may not remember the movie, the play or the book,, this is a tale about The Origin of the Species by Darwin and the teacher who brought it into the classroom to share with his students.  He is accused of violating an obsolete law based on religious belief that defames the science of the book.  Two very different lawyers battle over the concept with the country awaiting the outcome.  Is man allowed to think for himself or must all thought be based on literal interpretation of the Bible?

I read that in high school.  I should reread it...back then I was a little religious zealot, and I'd probably have quite a different perspective now.

My short book was Crome Yellow by Aldous Huxley (his first novel).  It's a satire set at an English country house, with a great cast of funny characters.  One of them gives some long semi-serious speeches about his ideas for a utopian society that sound familiar to someone who has read Brave New World.  but even this guy is portrayed as a buffoon.  There are no serious characters here.

The Great Divorce, by CS Lewis. I gave away my copy of Mere Christianity when I read this book. It's a short quick distillation of Mere Chrsitianity and since shelf space is tight, I opted for the Great Divorce.

ETA:

Would Flatland count as classic lit? Most of my classic stuff is thick and ponderous. Also, A Christmas Carol. That usually takes only two days to read out loud to the kids, so it counts as short for me.

Inherit the Wind must have been a required text for many high schools back in the day - copies of the book in the Bantam paperback always turn up at used book sales. It's a good book for teenagers, I think, short, easy to read, long on ideas.  Another short one by Huxley is The Genius and The Goddess, which probably may or may not give teenagers much to connect with, being about marriage, adultery, hero worship, heroes with feet of clay, out of control emotions, adult intellectuals with the emotions of little kids, etc.Erle Stanley Gardner's Perry Mason novels are short enough to read in six or seven hours; once started, gotta finish 'em, such is the narrative omph..

The Little Prince by Antoine de Saint Exupery. His plane going missing while on a flight in World War II was one of the great tragedies of Literature.

I read The Guide by R.K. Narayan (b. 1906 in Madras, India) . 208 pages in a Penguin Classic.

He is hard to get used to, but I have read several novels by him and, like one Encyclopedia of Literature I have says, one of the finest Indian writers of his generation writing in English. I think he is very very good.