“This comprehensive guide offers critical insight for those designing and implementing educational technologies that support personalized learning. Drawing from cognitive, motivational, and sociocultural research, it presents clear frameworks for integrating learner characteristics, such as interests, prior knowledge, and self-beliefs into adaptive systems. The content bridges theory and application, illustrating how data-informed personalization can shape responsive, inclusive, and effective learning experiences across diverse educational settings. It is a vital resource for anyone developing technology that seeks to align learning design with the individuality of each learner.”