Some people would say that those books cited in other answers are out-of-date. I have to disagree that Yang-Mills theory as presented in the 90's is outdated. In the last 30 years particle physics has not changed drastically. Perhaps the greatest news in this period of time were the discoveries of the Higgs particle, neutrino oscillations, top quark and tau neutrino. None of these changed our knowledge of gauge theories though.
As your post suggests you are more interested in gauge field theory and its mathematics formalism than in particle physics itself, thus a book like Baez & Muniain's (BM) cannot be outdated at all. Indeed this is one of the best places for a initial contact with differential geometry and topology for physicists. It is self contained, very well written, presenting the most important concepts in mathematics that are fundamental to the understanding of gauge theories. They avoid cumbersome proofs and prefer rather to sketch some results than to present them rigorously. This lack or mathematical rigor should not be a problem though since the aim of the book is just to introduce geometry and topology.
There is a book by B. Felsager: Geometry, Particles, and Fields which covers the mathematics of gauge theories exceptionally well. As well as Baez & Muniain, it presents geometry and topology but the focus here is more in calculations. It covers more topics compared to BM and it includes the basics of path integral quantization. If you want a rather newer book with similar topics, then try the 2013 The Geometry of Physics by T. Frankel. In my opinion both books are excellent and there is not any profound difference between them due to their age difference.
My favorite book on classical gauge theories is V. Rubakov's Classical Theory of Gauge Fields. The book dates 2002 and there is nothing we know today about classical gauge theories that is not covered there. Although the book does not put much emphasizes on geometry it is unique in many other aspects. For instance it gives thorough discussions about Lie algebras and groups (including representation theory), symmetries and the role of topology in gauge theories. It is mathematically self-contained, physically rigorous and detailed. Part of the book requires previous knowledge of Quantum Mechanics though. It has the style of lecture notes and focus and explicit calculations instead of phenomenology and hand waving arguments. It also has many good exercises, which keep showing up throughout the book. The only thing that bothers me is that for some reason the author decided to use all Lorentz indices down.
If you are interested in quantum aspects of gauge theories as well as particle physics, you can try Gauge Theories of the Strong, Weak, and Electromagnetic Interactions, 2nd ed. by C. Quigg. This is definitely up to date from particle physics point of view and covers from classical field theory to particle physics, also presenting an introduction to Grand Unified Theories. I do not think it is self-contained though. You will not learn Quantum Field Theory from this book and it has more the style of phenomenological and pragmatic book: you know the Feynmann rules and then obtain all you can from that. It is a straightforward sequence to Rubakov's book.
If you are interested in Grand Unification, one of the best places to start still is the Slansky's revision paper Group Theory for Unified Model Building. It focus mainly in lie algebras and representation theory. It might be a bit old, but those mathematical topics didn't change since 1983.
Those books, together with a good Quantum Field Theory book will give you a solid understanding of High Energy Physics and should give you condition to work in the field.
This post imported from StackExchange Physics at 2017-11-22 17:11 (UTC), posted by SE-user Diracology