Semiotic Engineering views HCI as computer-mediated communication between designers and users at interaction time. The system speaks for its designers in various types of conversations specified at design time. These conversations communicate the designers' understanding of who the users are, what they know the users want or need to do, in which preferred ways, and why. The designers' message to users includes even the interactive language in which users will have to communicate back with the system in order to achieve their specific goals. So, the process is in fact one of communication about communication, or metacommunication. [...] A Historical Note: René Jorna and Clarisse de Souza independently developed two different kinds of ‘semiotic engineering.’ Jorna’s was originally closer to Artificial Intelligence and Cognitive Science. His ideas were later developed and applied to decision support systems and organizational semiotics rather than HCI. The authors were introduced to each other (and to each other's version of 'semiotic engineering') only in 1996, in a Dagstuhl Seminar on Informatics and Semiotics organized by Peter B. Andersen, Mihai Nadin and Frieder Nake.