"Open textbooks are real, complete textbooks licensed so teachers and students can freely use, adapt, and distribute the material. Open textbooks can be downloaded for no cost, or printed inexpensively." (open.umn.edu/opentextbooks)

Each of the 18 (eventually 25) OpenStax texts is supported by a wide range of free and low-cost supporting materials, from homework to teaching guides. Available in free electronic versions and affordable printed copies.

OpenStax encourages educators to customize, remix, and build upon the core OpenStax books. Many who do create adaptations and supplemental materials share them here, in OpenStax CNX.

This open-access repository contains tens of thousands of learning objects across countless subject areas, and all of are free and easy to use in your own courses!

"Open SUNY Textbooks is an open access textbook publishing initiative established by State University of New York libraries and supported by SUNY Innovative Instruction Technology Grants.

This pilot initiative publishes high-quality, cost-effective course resources by engaging faculty as authors and peer-reviewers, and libraries as publishing service and infrastructure."

The Washington 45 are “courses selected from within the general education categories… at a public community, technical, four-year college or university in Washington state that will be able to transfer and apply a maximum of 45 quarter credits toward general education requirement(s) at any other public and most private higher education institutions in the state.”
(www.openwa.org/washington-45/)

"The World Digital Library (WDL) is a project of the U.S. Library of Congress, carried out with the support of the United Nations Educational, Cultural and Scientific Organization (UNESCO), and in cooperation with libraries, archives, museums, educational institutions, and international organizations from around the world. . . The principal objectives of the WDL are to:
Promote international and intercultural understanding;
Expand the volume and variety of cultural content on the Internet;
Provide resources for educators, scholars, and general audiences;
Build capacity in partner institutions to narrow the digital divide within and between countries."
(wdl.org/about)

License: CC-BY-NC-SA

The text requires students to be active learners — there are very few worked examples in the text, with there instead being 3-4 activities per section that engage students in connecting ideas, solving problems, and developing understanding of key calculus concepts; each section begins with motivating questions, a brief introduction, and a preview activity, all of which are designed to be read and completed prior to class; the exercises are few in number and challenging in nature.

The text focuses on the formal development of mathematics. Endorsed by the American Institute of Mathematics' Open Textbook Initiative.
License:

Author's website with study guides, solutions, videos, and supporting files:
https://sites.google.com/site/mathematicalreasoning3ed/

"In each chapter, authors present their unique views, insights, and strategies for writing by addressing the undergraduate reader directly. Drawing on their own experiences, these teachers-as-writers invite students to join in the larger conversation about developing nearly every aspect of the craft of writing. Consequently, each essay functions as a standalone text that can easily complement other selected readings in writing or writing-intensive courses across the disciplines at any level."

"In each chapter, authors present their unique views, insights, and strategies for writing by addressing the undergraduate reader directly. Drawing on their own experiences, these teachers-as-writers invite students to join in the larger conversation about the craft of writing. Consequently, each essay functions as a standalone text that can easily complement other selected readings in writing or writing-intensive courses across the disciplines at any level."

College writing teachers from around the web joined together to create this guide (see our Contributors list). The advice within it is based on contemporary theories and best practices. While the text was originally written for students in undergraduate writing classes, it can also be a suitable resource for other writers interested in learning more about writing for the web.

License: CC-BY-NC-SA

Topics include simulation modeling methods, case studies, exercises, and software tutorials.

License: CC-BY-NC-ND

Includes basic techniques for siding, aging, sexing, and stature estimation, as well as bone images.

This interactive story follows the life of a family trying to survive a brutal war in in Liberia and Sierra Leone during the 1990s.
Through a rich multimedia presentation that includes personal testimonies, images, maps, found artifacts, video, audio, and animations, Bent not Broken shows how one family survived the war and came to America in 2005.

Created and maintained by the University of Pennsylvania Libraries.