The "What is..." series of flyers provide an introduction to a specific method or technology and are intended to be read by engineers and scientists with no significant expertise or prior knowledge of the topic that is being discussed.

The Functional Mockup Interface has received significant attention over the last few years and this "What is.." flyer, authored by the NAFEMS Systems Modelling and Simulation Working Group, is intended to increase the awareness of the FMI standard and the problems that it can address.