Abstract
The aim of this study is to identify the dimensions of the unknown realm of content teaching knowledge and the evolution of its various conceptualizations from the beginning until now. From this approach, the historical research of the seven guidelines of how to do it (Short, 1991/1387) was considered. but this belief was questioned by Lee Shulman with Tassi of Dewey (1902) citing the difference between the logical understanding of scientists and the psychological understanding of teachers. The idea of knowledge of content education by Shulman in the eighties of the twentieth century opened a new window to the unknown realm of teachers' professional knowledge; with the passage of time and as a result Research has been done, this knowledge has been recognized and investigated at the levels of "group content teaching knowledge", "personal content teaching knowledge" and "content teaching knowledge in practice". According to contemporary experts, this knowledge has two general and unique natures is tomorrow The domain of content knowledge helps the teacher to transform the content of the subject knowledge into something that is understandable for the students. The process of developing content education knowledge is beyond content knowledge and requires thinking and reflection on how to form macro and micro cycles at two levels of personal content education knowledge and content education knowledge in practice.
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