The National Program for Textbooks and Teaching Materials (PNLD) is Brazil’s largest and most comprehensive educational book distribution initiative, ensuring free access to learning materials for millions of students in public schools. Over the decades, PNLD has played a crucial role in democratizing education, yet it has largely relied on printed textbooks with limited digital innovation. With the PNLD Digital initiative, the program is now undergoing a major transformation, seeking to modernize content creation, distribution, and accessibility. However, despite this shift, current PNLD digital textbooks remain static, rigid, and unable to leverage the full potential of digital learning technologies. The lack of interactivity, adaptivity, and immersive elements limits their ability to create engaging and personalized learning experiences, restricting students and educators from benefiting from cutting-edge educational tools. To address these challenges, this paper proposes the PNLD Digital Textbook Reference Model, a framework designed to establish a standardized yet flexible approach to developing interactive, immersive, and intelligent digital textbooks based on Web Publications. By defining a technological and pedagogical foundation, the model ensures that digital textbooks can move beyond static digital replicas and become truly enhanced learning resources. Grounded in multimedia learning principles and universal design for learning (UDL), the model guarantees that PNLD digital textbooks are not only engaging and interactive but also accessible to diverse learning needs. It establishes a structured open interactive textbook format, enabling the seamless integration of multimedia, real-time collaboration, and adaptive content while allowing for the modular inclusion of component-based learning objects. These components introduce AI-driven personalization, interactive exercises, dynamic assessments, and immersive AR/VR experiences, fostering deeper engagement and learner-centered education. To support scalability, interoperability, and accessibility, the proposed model integrates progressive web apps (PWA) and decentralized content distribution (IPFS/CDNs), ensuring that digital textbooks function both online and offline, eliminating infrastructure barriers in low-connectivity regions. Additionally, it defines a secure yet flexible approach to digital rights management (DRM), guaranteeing open access while protecting intellectual property. By leveraging AI-powered analytics, the model also facilitates adaptive learning pathways, allowing textbooks to adjust content difficulty, assessment types, and interactivity levels based on student progress and engagement patterns. This paper outlines the theoretical foundations, technical architecture, and implementation guidelines of the PNLD Digital Textbook Reference Model, presenting it as a blueprint for the future of digital education in Brazil. By empowering Brazilian publishers to create truly interactive, intelligent, and engaging learning materials, this model ensures that students, teachers, and educational institutions benefit from state-of-the-art digital learning solutions. As PNLD moves further into the digital era, this reference model provides a scalable and future-proof foundation to revolutionize the educational landscape, bridging the gap between traditional and next-generation learning experiences.

Keywords: National Textbook Program (PNLD), Interactive E-Textbooks, Web Publications.