“Zero Textbook Cost” or ZTC is the designation used in CUNYFirst to indicate that a course does not require students enrolled in the class to purchase a textbook or required readings. Instead, students may be assigned open educational resource (OER) materials, freely available materials (which may or may not be open, but are freely accessible for students made available through a subscription or purchase by CUNY and/or your campus Library, or they may have an “open” license that authorizes their use, or it could simply be that the copyright owner has chosen to make these materials freely available on the Internet ), or a combination of these.