Texts Introduction to Lie Algebras and Representation Theory by James Humphreys for 577, and Lie Groups: An Introduction through Linear Groups by Wulf Rossmann (probably supplemented by other materials in the spring) for 578-9.
Prerequisites: Algebraic background for 577-9: a familiarity with linear algebra and the rudiments of group theory (Math 506 is not necessary). Analytic/geometric background for 578-9: Math 544-5-6 taken concurrently or previously. It is possible (though not really desirable) to take 578-9 without having taken 577 if you're willing to accept a few theorems on faith.