The KR conference series serves as a biennial gathering for researchers working on different aspects of KR&R, and fosters communication, cross-fertilization of ideas, and collaboration across re- search boundaries. As a consequence, the lists of topics addressed at this and previous KR confer- ences are diverse and cover a broad range of substantial research areas. KR 2012 is a case in point. The most popular topics for submission to KR 2012 included answer set programming; description logics; nonmonotonic reasoning; argumentation; belief merging, revision, and update; and KR and databases.

Workshop on Knowledge-Intensive Business (KR&R) has long been a vibrant and exciting Processes (KiBP 2012). It has emerged from 256 registered abstracts. It was significantly more an understanding of how to store, retrieve, and interact than the 161 submissions to KR 2002, but somewhat with knowledge, and at the development of fewer than the record set at KR 2008 of 251 submissions. John McCarthy, recognized tasks such as planning, diagnosis, argumentation, by many as the founder of AI and KR, passed away and belief revision. KR 2012 will pay tribute to John gathering for researchers working on different aspects through an invited lecture by Leora Morgenstern of KR&R, and fosters communication, crossfertilization entitled "rough the Lens of Drosophila: John Mc-of ideas, and collaboration across research Carthy's Quest for Human-Level Artificial Intelligence."