I have studied Multi-variable calculus. Now, I am thinking to study Tensor calculus. As it is an important topic in [General Relativity](https://en.wikipedia.org/wiki/General_relativity). I have found [a book called (Mathematical Methods in Physics: Distributions, Hilbert Space Operators, Variational Methods, and)](https://www.pdfdrive.com/mathematical-methods-in-physics-distributions-hilbert-space-operators-variational-methods-and-applications-in-quantum-physics-e175905059.html). Should I read that book? I want to learn Math tools. And, is there something I should read before studying Tensor Calculus?
