If you are a student or self-learner:
If you are interested in downloading Salas and Hille's Calculus PDF, there are several options available:
Pros:
While rigorous, the explanations are noted for being "clean" and logical. Important Note on Digital Versions
Vectors, partial derivatives, multiple integrals, and vector analysis (including Green’s, Stokes’, and Divergence theorems). Why Students Seek This Text