Ebook: An Introduction to Lie Groups and Lie Algebras

this is a wickedly good book. it's concise (yeah!) and it's well written. it misses out on lots of stuff (spin representations, etc..). but once you read this book you will have the formalism down pat, and then everything else becomes easy.

if you put in the hours to read this book cover to cover -- like sitting down for 3 days straight 8 hours a day, then will learn the stuff. if you don't persevere and get overwhelmed with the stuff that is not clear at the beginning, then you will probably chuck it out the window.

lie groups and lie algebras in 200 pages done in an elegant way that doesn't look like lecture notes cobbled together is pretty impressive.