Available data on the effects of suction and injection on skin friction are summarised and compared. It is shown that injection into a turbulent boundary layer can produce a skin friction coefficient lower than the laminar value at the same Reynolds number on an impermeable plate. The College of Aeronautics was founded in 1946 and was granted university status in 1969 becoming the Cranfield Institute of Technology. In 1993 it changed its name to Cranfield University.