In the three parts of this paper, it will be shown how this idea is increasingly deepened in Vygotsky’s texts. In his earliest writings, he demonstrates that imagination is made up of elements of the real and creates the real. Later on, he adds a new dimension: “crystallized imagination,” which enables one to grasp imagination as a cycle. To deepen the relationship between imagination and reality, it is necessary to articulate it with thought. As is shown in part two, a philosophical detour through Lenin reading Hegel in the Philosophical Notebooks enables Vygotsky to design a concept of concept based on imagination. Thought and imagination can thus be conceived as a contradictory unit—as shown in part three—reflecting reality in a zigzag relationship with the real, allowing the construction of the “mentally concrete” [ geistig Konkretes ].