Deep-inelastic scattering with muons

A vigorous, successful experimental programme on deep-inelastic muon–nucleon scattering has been carried out with the CERN SPS muon beam that started in 1978 and is still actively pursued today. This paper reviews landmark results from this programme, focusing on the precision measurement of scaling violations and the determination of the strong coupling constant α s , measurements of spin-dependent structure functions, and of the spin structure of the proton.