The book "Business Process Model and Notation" documents the results of the fourth workshop on Business Process Model and Notation (BPMN), which took place in September 2012 in Vienna. This event served as a platform for academics and practitioners interested in modeling business processes with BPMN, which is widely recognized as the de facto standard in this field. The workshop covered both scientific and practical aspects and included the presentation of nine selected papers, carefully chosen from 22 submitted contributions. The submissions underwent a rigorous review process, with each paper evaluated by three members of the program committee. In addition, the book contains an extended summary of the keynote speech from the workshop.