Digital textbooks have become central to the evolution of technology-supported learning, shifting from static replicas of print materials to dynamic, intelligent platforms that personalize and enrich the learning experience. However, the classification of digital textbooks in educational research remains fragmented, often failing to capture their developmental trajectory and their broader role in supporting educational technologies.

This paper introduces an evolutionary taxonomy that conceptualizes digital textbooks as key enablers of technology-supported learning, structured across five generations: Digitized, Rich, Interactive, Immersive, and Intelligent. Each generation reflects a significant shift in how digital textbooks integrate technological advancements and pedagogical strategies to support learner engagement, accessibility, and personalized instruction.
(a) Digitized Textbooks serve as the foundational layer, offering static digital versions of print materials.
(b) Rich Digital Textbooks incorporate multimedia elements, increasing learner engagement and accessibility without altering the pedagogical model.
(c) Interactive Textbooks introduce active learning through self-assessment tools, feedback loops, and collaborative features.
(d) Immersive Textbooks harness Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR) to support experiential and spatial learning.
(e) Intelligent Textbooks leverage AI, adaptive learning systems, and data analytics to deliver personalized, real-time support and content pathways.

Positioned within the broader context of technology-enhanced learning, this taxonomy underscores how digital textbooks evolve from passive content containers to dynamic learning environments. The paper also discusses key challenges—including cognitive overload, digital inequality, privacy concerns, and a lack of interoperability standards—as well as emerging opportunities in adaptive learning, credentialing, and Open Educational Resources (OER).

By mapping the progression of digital textbooks, this framework not only clarifies their educational potential but also informs the design of future learning technologies that are inclusive, intelligent, and learner-centered.

Keywords: Digital and Interactive Textbooks, Technology-Enhanced Learning, Adaptive Learning Platforms, Educational Taxonomy, Learning Resource Design, Personalized Learning.