"Educational Algebra" offers a comprehensive theoretical and empirical analysis of school algebra instruction. The book examines the complex semiotic concepts and the historical development of algebraic ideas to create a deeper understanding of the learning process. It adopts a methodological approach that allows for the interpretation of specific phenomena that arise when learning symbolic algebra. This includes the development of personal sign systems that learners create on their journey to understanding mathematical symbols. The interdisciplinary perspective of the book integrates insights from linguistics, psychology, and mathematics education to illuminate the challenges and advancements in algebra teaching.