The chapter introduces the concept of ensemble-based classifiers, which involve integrating multiple models to improve prediction performance. The authors, Lior Rokach, review existing ensemble techniques and provide a tutorial for practitioners interested in building ensemble systems. The chapter begins by defining supervised learning and the role of classifiers in classifying patterns into categories. It then discusses the ensemble methodology, highlighting how it combines multiple individual classifiers to create a more accurate model. The chapter references historical figures like Condorcet and Galton, who demonstrated the power of combining multiple opinions or predictions to achieve better outcomes. It also cites James Surowiecki's book "The Wisdom of Crowds," which argues that under certain conditions, collective wisdom can lead to superior decisions compared to individual ones. The chapter emphasizes the criteria for a wise crowd, including diversity, independence, decentralization, and aggregation of information.The chapter introduces the concept of ensemble-based classifiers, which involve integrating multiple models to improve prediction performance. The authors, Lior Rokach, review existing ensemble techniques and provide a tutorial for practitioners interested in building ensemble systems. The chapter begins by defining supervised learning and the role of classifiers in classifying patterns into categories. It then discusses the ensemble methodology, highlighting how it combines multiple individual classifiers to create a more accurate model. The chapter references historical figures like Condorcet and Galton, who demonstrated the power of combining multiple opinions or predictions to achieve better outcomes. It also cites James Surowiecki's book "The Wisdom of Crowds," which argues that under certain conditions, collective wisdom can lead to superior decisions compared to individual ones. The chapter emphasizes the criteria for a wise crowd, including diversity, independence, decentralization, and aggregation of information.