This research proposes an analysis of Portuguese textbooks included in the Guia do Livro Didático distributed by the MEC for schools. The main purpose of this analysis is to enable discussions about (a) the current mechanisms for evaluating this kind of book, (b) the use of the image in textbooks, (c) the inclusion of other genres in their content and, essentially, (d) about the possible contribution of designers to the production of textbooks in Brazil. Understanding the object as a genre composed by extracts from other media, we study the points that determine their production, both in relation to the goals of its educational content - the Parâmetros Curriculares Nacionais (PCNs) - and in relation to their official and social approval of the book as a legitimate didactic product – brought by the Programa Nacional do Livro Didático (PNLD). In light of visual grammar, Gestalt and multiliteracies theories, in the perspective of Design in reading practices, the priority is to exam the main Portuguese teaching textbooks, since it is the main support for reading skills development and a kind of media that can, from the representation of various other media inside, develop reading expertise. As a multimodal object, being the result of the combination of visual and verbal languages, the book requires the participation of the designer in a collective work. In examining the conditions of legitimacy that define the conditions for its production and samples that are in use nowadays, it is concluded that there is a gap between the market, the official textbooks evaluation programs and the Design courses models. This gap prevents the development of graphic designs that understands and explores the parameters, enabling an assessment that meets the demands of the contemporary society and seeing the designer as an co-author needed in all stages of planning and production of textbooks in Brazil.