I love it when literature is combined with grammar. I found a great quote by the famous author, James Thurber, discussing the inappropriate use of who and whom.

The number of people who use "whom" and "who" wrongly is appalling. The problem is a difficult one and it is complicated by the importance of tone, or taste. Take the common expression, "Whom are you, anyways?" That is of course, strictly speaking, correct — and yet how formal, how stilted! The usage to be preferred in ordinary speech and writing is "Who are you, anyways?" "Whom" should be used in the nominative case only when a note of dignity or austerity is desired. For example, if a writer is dealing with a meeting of, say, the British Cabinet, it would be better to have the Premier greet a new arrival, such as an under-secretary, with a "Whom are you, anyways?" rather than a "Who are you, anyways?" — always granted that the Premier is sincerely unaware of the man's identity. To address a person one knows by a "Whom are you?" is a mark either of incredible lapse of memory or inexcusable arrogance. "How are you?" is a much kindlier salutation.
~James Thurber
Ladies' and Gentlemen's Guide to Modern English Usage

~Guide to Grammar and Writing website