This special issue of Jetai is devoted to papers concerning the knowledge representation language of Conceptual Graphs. The intent of this overview is to give readers a general understanding of what conceptual graphs are and how the formalism operates. Unfortunately, this overview is somewhat brief; however, it should provide a sufficient background to enable the reader to follow the papers in this issue. Interested readers should refer to John Sowa's book, Conceptual Structures, for a fuller account