*The Ordinary Differential Equation Project*, an open source textbook designed to teach ordinary differential equations to undergraduates, is a work in progress. The latest and most up-to-date version of *The Ordinary Differential Equation Project* can be found at HTML Version. In addition, there is a Runestone Version.

We recommend the online version in Runestone, since it is updated weekly. The Runestone version contains working Sage cells and allows students to respond to reading questions directly in the textbook.

The book’s strengths include a wide range of exercises, both computational and theoretical, plus many nontrivial applications. Technology is integrated into the textbook using the open source system, Sage. In addition, there are reading questions and class activities in each section. Reading questions are intended to be completed prior to class. These questions provide an opportunity for students to familiarize themselves with the material before it is covered in class. Reading questions also allow the instructor a chance to modify a lesson according to the student responses. Classroom activities provide an opportunity for students to work problems in class. I often have students work on classroom in small groups at the board. Each chapter ends with a section containing several extended projects.

Although *The Ordinary Differential Equations Project* is still in development, the book is now being used at several universities. For this reason, I have begun declaring annual editions each fall with a snapshot editions whenever appropriate. The latest source can be found on GitHub (https://github.com/twjudson/odeproject-public) and the Runestone edition is updated weekly.

- Full Text, 2023 edition (PDF, 15 MB, July 24, 2023)
- Full Text, 2022 edition (PDF, 16.8 MB, July 30, 2022)
- Full Text, 2021 edition (PDF, 25.2 MB, August 21, 2021)
- Full Text, 2020 edition (PDF, 25.2 MB, August 1, 2020)
- Full Text, 2019 edition (PDF, 25.2 MB, August 21, 2019)
- Full Text, 2018 edition (PDF, 24.2 MB, August 19, 2018)

*The Ordinary Differential Equations Project* is written in PreTeXt. PreTeXt is an authoring and publishing system for authors of textbooks, research articles, and monographs, especially in STEM disciplines. Once a book has been written in PreTeXt different outputs can be produced such as PDF, HTML, EPUB, Jupyter Notebooks, and even braille. The PreTeXt source for *The Ordinary Differential Equations Project* is available at GitHub.