So I was inspired by one of the recent topics to think of how to improve my math skills in order to be better prepared for graduate school (in my case, experimental HEP). I have taken only linear algebra as far as upper division math classes and I can't take any other due to limited time and the fact that I have already graduated... However, I don't want to feel like a complete idiot in the first year of grad school so I am willing to sit down and master some mathematical concepts that are commonly encountered in physics.

The math for physical sciences at my school is taught out of Mathematical Methods for the Physical Sciences by Boas, so that would be one natural choice, but before I dig in I would like to know what do you think.

If you were going to go to grad school at a desert island for your first year and you were allowed to bring only one math textbook, which one would you take?