Michael Spivak has written multiple books. Which one do you mean?

Calculus on Manifolds. I'd recommend Hubbard and Hubbard over that as it's a little easier read with the same material.

> I'd recommend Hubbard and Hubbard over that as it's a little easier read with the same material.

John Hamal Hubbard, Barbara Burke Hubbard - Vector Calculus, Linear Algebra and Differential Forms: A Unified Approach