Should I take a semester-long differential geometry course (in lieu of a thermo/stat mech course, which while not terribly challenging would prepare me for qualifiers, etc), or should I just jump into GR and maybe pick up a mathematical methods in physics course later? I first learned partial dif eqs in an advanced e&m course, will differential geometry and general relativity be a similar deal, or do I really need a solid foundation in it before starting? To be more clear: I'm a grad student, differential geometry and thermo/stat mech are both mixed undergrad/grad courses. Thermo/stat mech is probably similar in content to a mixed undergrad/grad course I took a few years ago as an undergrad. I'm sure taking it again as a grad student would improve my stat mech, but I'm also a little hesitant to go through it with undergrads forcing us to cover everything I've already done before. On the other hand, I'm somewhat worried that either 1. differential geometry could turn into a time consuming exercise in mathematics that won't really be used ever again or 2. I will end up kind of screwed by not taking it. I will sit in on differential geometry tomorrow and see what I think of it.