Acknowledgements Acknowledgements

This text began as my sabbatical project in the fall semester of 2018, during which I wrote most of the material. For the sabbatical leave, I express my deep gratitude to Grand Valley State University for its support of the project, as well as to my colleagues in the Department of Mathematics and the College of Liberal Arts and Sciences for their endorsement of the project.

The beautiful full-color .eps graphics, as well as the occasional interactive JavaScript graphics, use David Austin's Python library that employs Bill Casselman's PiScript. The .html version of the text is the result Rob Beezer's amazing work to developthe publishing language PreTeXt (formerly known as Mathbook XML); learn more at pretextbook.org. I'm grateful to the American Institute of Mathematics for hosting and funding a weeklong workshop in Mathbook XML in San Jose, CA, in April 2016, which enabled me to get started in PreTeXt. The ongoing support of the user group is invaluable, and David Farmer of AIM is has also been a source of major support and advocacy. Mitch Keller of Morningside College is the production editor of both Active Calculus: Single Variable and this text; his technical expertise is a gift.

This first public offering of the text in January 2019 will benefit immensely from user feedback and suggestions. I welcome hearing from you.