Scale-up Engineering is an extremely effective tool for engineers of all disciplines. It is based on the description of technical objects by complete sets of dimensionless numbers. The scale-up laws are helpful in solving engineering problems by simple or small-scale experiments. Thus, the dimensionless numbers and scale-up laws are used in many fields of natural and engineering sciences. Classical fields of applications are fluid mechanics, heat and mass transfer, mechanics (statics, dynamics, stress and strain), and aeronautics. Novel fields of applications are reaction engineering, acoustics and space sciences.