Technology is changing the way books are read and the way courses are taught. At many universities, technology is also changing what is being taught, and at Amazon, more eBooks are being sold than print editions, even though the Kindle is only four years old. While present eBooks are largely digital versions of paper books, future eBooks, and especially eTextBooks, are sure to be quite different from their present form, as are future courses. A complete eTextBook with multiple executeable elements has been created, an early draft has been placed on line, and Princeton Press is attempting to publish it. While future technologies promise vastly improved executeable papers, the created eTextBook highlights some of the features now possible with existing technologies. The project combines 15 years of development in Computational Physics Web enhancements and 20 years of Computational Science and Computational Physics textbook developments into a prototype eTextBook that combines text, executebale equations and figures, animations, simulations and video-based lecture modules. A demonstration will be given.