Sierra’s most well-known works involve hiring laborers to complete menial tasks. These works are meant to elucidate the nature of the laborer within capitalist society, how the laborer sells his physical labor and thus his body, political issues such as immigration and continual immigrant poverty in Capitalist countries, the nature of work in Capitalist society, and the isolation of economic classes. He achieves this through a number of techniques that present these themes and also question the nature of the art institution.