Human cognition necessarily involves the process of projecting internal representations to the real world. However, little effort has been made to explore its process and mechanism. This paper aims at stressing the importance of projection for the total understanding of mind. Next, we propose that there are three types of projection: (proper) projection, misprojection, and fictional projection, depending on the relationships between internal representations and external objects. Then, we discuss possible mechanisms of projection, based on the idea of “overprint” developed by a Japanese philosopher Omori (1982). Finally, we contrast the notion of projection with alternative explanations that deny the notion of projection.