There has been always a strong debate between professionals of the practicing world of architecture and the educationalist and theorists in architecture about the importance of theory and its impact in practice as the young graduates find it very difficult to readily adopt to the world of practice even after professionally qualified as architects. In this regard research is being conducted and trying to identify the factors leading to this Gap. we are trying to “Rationale of Application of Theory Inputs in Architectural Practice”. This paper is the first part of the study and is only a review paper based on literature review and perception of various architects in regard of what is theory in architecture and its importance.