Curriculum is one of the broadest and most complex concepts in the study and development of formal learning processes. Within the broad idea of curriculum we can include every component of the learning process, every participant, as well as every personal or conceptual relationship between all of these. Construction of curriculum depends on the participants’ –especially educators- knowledge of it, and how this understanding is less or more profound and global. Each part of curriculum is a crucial part of the mechanism of the learning process, and consequently, depending on the teachers’ and learners’ (participants’) knowledge of curriculum, therefore, they can combine all these parts to raise a solid frontier between what is correct or not correct to learn in a delineated and inflexible learning environment, as well as they could mix these elements in a favorable atmosphere in order to learn together in a flexible learner centered learning process. Unfortunately, curriculum has become a too wide and undefined field, so there is a grave lack of clear knowledge about curriculum (theory and practice) in our educators.