  In this Thesis we present a comprehensive study of perturbative and
non-perturbative non-Abelian gauge theories in the light of gauge-fixing
procedures, focusing our attention on the BRST formalism in Yang-Mills theory.
We propose first a model to re-write the Faddeev-Popov quantisation method in
terms of group-theoretical techniques and then we give a possible way to solve
the no-go theorem of Neuberger for lattice Yang-Mills theory with double BRST
symmetry. In the final part we present a study of the Batalin-Vilkovisky
quantisation method for non-linear gauges in non-Abelian gauge theories.
