Successful communication depends not only on our knowledge of language but also on our knowledge of context. It is commonly assumed that most communicative interactions take place within non-defective contexts. So, it is often assumed, if we want to understand how communication functions, we should focus on non-defective contexts. In this chapter Peet hopes to persuade you that defective contexts are more ubiquitous than we typically assume and that, as a result, they should occupy a larger role in our linguistic theorizing than they typically occupy. In doing so, he draws attention to a number of pressing social and theoretical issues which arise once we start to consider defective contexts.