I have encountered the section on non-Abelian gauge theories in Peskin and Schroeder's QFT textbook, and although I am comfortable with the derivation of the Yang-Mills Lagrangian they present, the discussion that follows on Lie groups / algebras and their representation I am struggling with.
The relevant section of the book seems to be written as a review of the material for people already familiar with it, rather than a first introduction, so I am struggling to understand the justification for statements they make offhand.
I would appreciate it if anybody could point me towards an alternative source for this material presented in reasonable detail at a relatively elementary level. What P&S tries to cover in the space of eight pages amounts to the basics of the representation of compact Lie algebras (irreducible, conjugate, fundamental and adjoint representations), products of representations, and Casimir operators, to give a feel for the material I would like to learn before proceeding in P&S.