You may have learned
that ending a sentence with a preposition is a serious breach of grammatical etiquette. It doesn't take a grammarian to spot
a sentence-ending preposition, so this is an easy rule to get caught up on (!). Although it is often easy to remedy the
offending preposition, sometimes it isn't, and repair efforts sometimes result in a clumsy sentence. "Indicate the book you
are quoting from" is not greatly improved with "Indicate from which book you are quoting."
Based on shaky historical
precedent, the rule itself is a latecomer to the rules of writing. Those who dislike the rule are fond of recalling
"That is nonsense up with which I shall not put."
We should also
remember the child's complaint:
"What did you bring that book that I don't like to be read to out of up