The subject of a poem is the idea or thing that the poem concerns or represents. Looking for the poem's subject is natural. Almost all poetry has messages to deliver — lots of them, profound and diverse as stars. But these messages are sometimes hidden, and you have to read attentively to make them out. The theme in a story is its underlying message, or 'big idea.' In other words, what critical belief about life is the author trying to convey in the writing of a novel, play, short story or poem? This belief, or idea, transcends cultural barriers. It is usually universal in nature