What is Spivak calculus?

Spivak Calculus refers to the book "Calculus" by Michael Spivak. He is a mathematician who founded Publish-or-Perish Press, and he also authored the five-volume "Comprehensive Introduction to Differential Geometry."

Spivak's book "Calculus" is considered one of the more rigorous texts on introductory calculus, taking students from very basic algebraic equations and systems and challenging them to see important relationships throughout differential and integral calculus. If a student sees that this text is being used in a calculus course, it is likely that the course emphasizes pure mathematics, leaning towards differential geometry and manifolds rather than physics problems and applied mathematics.