Solving the Problem with Algebra.- The Core of Algebra: Reflections on its Main Activities.- Responses to ‘The Core of Algebra’.- The Early Development of Algebraic Reasoning: The Current State of the Field.- A Toolkit for Analysing Approaches to Algebra.- Research on the Role of Technological Environments in Algebra Learning and Teaching.- Computer Algebra Systems and Algebra: Curriculum, Assessment, Teaching, and Learning.- The History of Algebra in Mathematics Education.- Symbols and Language.- Teachers’ Knowledge and the Teaching of Algebra.- The Teaching and Learning of Tertiary Algebra.- Goals and Content of an Algebra Curriculum for the Compulsory Years of Schooling.- Algebra: A World of Difference.