What is Laicite by Sheidān Vasiq can be probably taken as the briefest and yet the most profound Persian work which provides a complete historical and conceptual view of laicite and secularism. Vasiq has examined these words from the indigenous perspectives, and also challenged the Iranian scholars’ opinions. However, despite its integrity in scrutinizing the meaning of laicite and secularism, this book is lack of methodological consistency. In this study, the author intends to write a review upon this book. In this regard, he presents the article in two parts. In the first part, he criticizes the book in terms of its definition of the vocabularies from different aspects: examining the literal meaning versus the idiomatic meaning of the words, the difference between the old and modern meaning, mixing the real and favorable meaning, and reflecting upon the meaning of “the separation of religion from politics” and “the separation of Islam institution from politics institution”. Since Vasiq has quoted and criticized some of the Iranian scholars’ theories about laicite and secularism at the end of his book, the writer, in the second part, is going to bring up these theories, and Vasiq’s review upon them followed by his own criticism of Vasiq’s.