The Calculus Collection is a useful resource for everyone who teaches calculus, in secondary school or in a college or university. It consists of 123 articles selected by a panel of veteran secondary school teachers. The articles focus on engaging students who are meeting the core ideas of calculus for the first time and who are interested in a deeper understanding of single-variable calculus. The Calculus Collection is filled with insights, alternative explanations of difficult ideas, and suggestions for how to take a standard problem and open it up to the rich mathematical explorations available when you encourage students to dig a little deeper. Some of the articles reflect an enthusiasm for bringing calculators and computers into the classroom, while others consciously address themes from the calculus reform movement. But most of the articles are simply interesting and timeless explorations of the mathematics encountered in a first course in calculus.