This book is the result of a national, non-profit project to develop a high-quality, introductory astronomy textbook that is free to students. The publisher, OpenStax, is located at Rice University and supported by several major foundations (including the Gates Foundation.) With the help of over 75 astronomers and astronomy educators, the textbook has been adapted, expanded, and updated from earlier textbooks the three authors have written. The book is not only free, but open source, which means you can use it as is, or develop your own electronic version of it, selecting only the sections you teach, adding your curriculum materials, etc. It is now available for review and adoption at: https://openstax.org/details/astronomy Featuring such current topics as the results from the New Horizons exploration of Pluto, the classification of exoplanets from Kepler and other projects, and the discovery of gravitational waves, the book is up-to-date and peer reviewed. At the same time, it is written in everyday language specifically for non-science majors, with many analogies from students’ lives, clear diagrams, the latest color images, and occasional touches of humor. Math boxes throughout the chapters put topics on a quantitative footing for those who want to use math in the course. Each chapter has math problems at the end. However, if you don’t use math, these boxes and problems can easily be skipped. Chapters also include suggested collaborative group activities, especially useful for discussion sections, links to web resources, biographies of astronomers, interdisciplinary connections, and much more. Ancillary materials are also being developed and the book will be compatible with several class management software systems. See also our open resource hub at: https://www.oercommons.org/groups/openstax-astronomy/1283/?utm_source=hub27