I made the mistake of purchasing Toward the Mathematics of Quantum Field Theory by Paugam, the problem being I have more of a background in physics/engineering than in mathematics. Despite my error, I'd like to read it anyway, though I find myself lacking the prerequisite knowledge. I have a rudimentary understanding of variational calculus and differential forms, but clearly something more is required.
Hence, if you have read the book or know of its contents, could you suggest a list of topics and/or resources to gain the necessary mathematical background?