Judging from its name, "Lullaby" should be an easy poem. Lullabies are usually sung to kids, after all. But it's actually a lot more difficult. Auden's word order (also known as his syntax) and his line breaks (also known as enjambments) can make the poem difficult to follow. Throw in Venus, some screaming madmen, and a weirdo hermit, and you've got yourself a difficult poem. That said, it is your basic love poem and the message comes across loud and clear: nobody's perfect and that's okay.