The complexity of socio cultural contexts and, consequently, of the school requires an explicit planning that can offer the didactical action a rhizomatic and generative vision.In such direction the models of curriculum of the last century, often characterized by a linear logic, lost much of their efficacy and cannot have an impact any longer with the complexity of reality and of the group class.Reflecting on the curriculum means catching the characterizing elements of the current contexts at the pedagogical and didactical level and reflecting on the elements of continuity and discontinuity from the past that could facilitate the change from linear models to recursive models.  The present article is organized into two parts: in the first there is a comparison between the present and the past, while in the second there is a review of the main contributions that from the Seventies of the last century have provided the basis to define the role and the structure of the curriculum.The article "the curriculum, the macro design and the micro design, and the curriculum transposition, present in the same issue, is the logic continuation of the present contribution.