Object Process Methodology (OPM) is a conceptual modeling language and methodology for capturing knowledge and designing systems, specified as ISO/PAS 19450. Based on a minimal universal ontology of stateful objects and processes that transform them, OPM can be used to formally specify the function, structure, and behavior of artificial and natural systems in a large variety of domains. OPM was conceived and developed by Dov Dori. The ideas underlying OPM were published for the first time in 1995. Since then, OPM has evolved and developed. In 2002, the first book on OPM was published, and on December 15, 2015, after six years of work by ISO TC184/SC5, ISO adopted OPM as ISO/PAS 19450. A second book on OPM was published in 2016. Since 2019, OPM has become a foundation for a Professional Certificate program in Model-Based Systems Engineering - MBSE at EdX. Lectures are available as web videos on Youtube. Overview Object Process Methodology (OPM) is a conceptual modeling language and methodology for capturing knowledge and designing systems. Based on a minimal universal ontology of stateful objects and processes that transform them, OPM can be used to formally specify the function, structure, and behavior of artificial and natural systems in a large variety of domains. Catering to human cognitive abilities, an OPM model represents the system under design or study bimodally in both graphics and text for improved representation, understanding, communication, and learning. In OPM, an object anything that does or does not exist. Objects are stateful—they may have states, such that at each point in time, the object is at one of its states or in transition between states. A process is a thing that transforms an object by creating or consuming it, or by changing its state. OPM is bimodal; it is expressed both visually/graphically in Object-Process Diagrams (OPD) and verbally/textually in Object-Process Language (OPL), a set of automatically generated sentences in a subset of English. A patented software package called OPCAT, for generating OPD and OPL, is freely available. History Around that time, in 1991, Dov Dori, who then joined Technion – Israel Institute of Technology as faculty said in his 2016 book Model-Based Systems Engineering with OPM and SysML that he: Dori published the first paper on OPM in 1995. In 1997, Unified Modeling Language (UML), by the Object Management Group (OMG), became the de facto standard for software design. UML 1.1 was submitted to the