Upon first read, Craig Raine's "A Martian Sends A Postcard Home", that was written in 1979, may seem to be a poem about random happenings on Earth. However, while reading the poem in depth and interpreting the poem it can be read as a Martian that was unfamiliar with Earth and its culture. This poem is filled with metaphors. In Craig Raine's poem "A Martian Sends A Postcard Home" the very literal in essence it is a Martian writing to his people back home. The theme of difference is represented by the Martians lack of the proper words and terms to describe everyday things. The Martian in the poem does this because he has a conceptual viewpoint.
The first time we see a metaphor is in the first line, "Caxtons are mechanical birds with many wings." (1) I interpreted this as somebody must have pointed at a book and called it a Claxton, or just referred to it as a Claxton, but the Martian might have thought it was a mechanical bird, seeing how an open book does resemble a bird with many wings.
The Martian also notices that some books or "mechanical birds" are more important than others because of what is inside.
In the next stanza the Martian says books "cause the eyes to melt," (3) probably referring to people when they cry as they are reading. The next line in that stanza shows that at times the people yell or scream because of the books and what they are reading. In stanza three the Martian has never seen a "mechanical bird" fly but he has seen them perched on hands before. Someone could have construed this stanza as, he never saw a book fly, but he does see them being held by people...