Thor I. Fossen (born in Bodø, Norway in 1963) is a naval architect and a cyberneticist. He was appointed professor of guidance, navigation and control at the Department of Engineering Cybernetics, Norwegian University of Science and Technology (NTNU) at age 30. Fossen has been elected to the Norwegian Academy of Technological Sciences (1998) and elevated to IEEE Fellow (2016). His expertise is on mathematical modeling, vehicle dynamics, marine craft, unmanned vehicles, inertial navigation systems and nonlinear control theory. He received the MSc and PhD degrees in Marine Technology and Engineering Cybernetics both from NTNU. Professor Fossen is one of the founders of the DNV-GL company Marine Cybernetics (www.marinecybernetics.com) where he was Vice President R&D in 2002-2008. He received the Automatica Prize Paper Award in 2002 and the Arch T. Colwell Merit Award in 2008.