Abstract
Since Open Education Resources (OER) approved in the early 2000s, it has grown as a major source of free learning materials for higher education; it is available for anyone to reuse, revise and redistribute based on the Creative Commons (CC), ready to give people worldwide equal access to collective knowledge and quality education by making good quality lectures, curricula, and books. In this paper, a brief history of OER is stated, then focused on categories of OER, ending with a discussion of the impact on reducing spending money on books compared to (Open Access) OA and OER