Calculus is one of my favorite areas of math, primarily because it is both extremely powerful and intuitively understandable. However, many classes and textbooks ruin the magic of calculus by focusing on formulas and theorems without explaining why they are true.
Enter Intuitive Explanations, a collection of intuitive, graphical, easy-to-understand explanations of many of the more complex concepts in calculus. It covers topics such as the formal definitions of limits and integrals, the product and quotient rules, the fundamental theorem of calculus, theorems about the convergence of sequences and series, and the definitions and theorems of vector analysis. The document also includes links to many other resources helpful for learning calculus around the Web.