Artificial Intelligence is the field of computer science that seeks to build
autonomous machines—machines that can carry out complex tasks without
human intervention. This goal requires that machines be able to perceive and
reason. Such capabilities fall within the category of commonsense activities that,
although natural for the human mind, are proving difficult for machines. The
result is that work in the field continues to be challenging. In this chapter we
explore some of the topics in this vast area of research.