The Prime of Miss Jean Brodie by Muriel Spark
Miss Jean Brodie is a teacher at the Marcia Blaine school for girls. Six 10-year-olds girls are assigned to her. But Miss Jean Brodie is no ordinary teacher. She's a progressive teacher in a conservative school. She admires Franco, Mussolini and Hitler. She's in love with a married man but moves in with someone else. And she is willing to discuss her love life with "her girls".
Miss Brodie has decided to mold her girls into the "crème de la crème". And they soon do turn out to be distinctive. Miss Brodie is just as likely to talk about her love life as she is about art. She is less likely to talk about math or science. The headmistress, Miss Mackay, disparately wants a reason to dismiss her.
"The Prime of Miss Jean Brodie" is a novella. It's a small book that tells of the lasting impression Miss Brodie has on her girls. The story is told out of sequence, giving hints about what is to come. In the first few ages you learn one of the girls will betray her. But it's not until the end of the book that you find out who or why.