Yeah... I'd be hesitant to buy a whole book. This is one of the topics where some expositions are really bad, some are really good, and some people just can't a

Yeah... I'd be hesitant to buy a whole book. This is one of the topics where some expositions are really bad, some are really good, and some people just can't agree on which are bad and which are good. I've always had best luck just pulling up 8 different articles and reading them in parallel, hoping it eventually sticks. (Which I realize is the least helpful possible reply.) The textbook Peskin&Schroeder is standard in this field. "If" you can find a PDF online, there's a chapter introducing gauge theories (the chapter on yang-mills) that has a reasonably clear explanation near the beginning, I think.