In this chapter, we start by defining and illustrating the notions of discourse relations and connectives. We will see that even though the role of discourse connectives is to make discourse relations explicit in discourse, their use is not necessary for a discourse relation to be communicated. Conversely, connectives are not always associated with a specific discourse relation: many of them can convey various relations depending on the context. Another goal of this chapter is to situate discourse relations and connectives within the more general concepts of discourse cohesion and coherence. We will see that connectives represent one type of cohesive tie and that discourse relations are crucial elements ensuring local coherence within a discourse. In the last part of the chapter, we present some important underlying methodological and theoretical choices that were made when selecting the topics covered in the book and the data presented in each chapter. We also emphasize that the study of discourse connectives and relations has many interfaces with other domains of linguistic analysis such as semantics, pragmatics and syntax.