This book aims to provide a comprehensive overview of the role of Error Analysis in understanding how second language learners develop their overall language proficiency, as well as its implications for language teaching and learning. The study of errors in second language learning has a rich history. spanning several decades of research and theoretical development. From the early days of Contrastive Analysis to the most recent insights, error analysis has been a fundamental aspect of understanding the process of second language acquisition. In this book, we will delve into various aspects of Error Analysis, including its theoretical foundations, methodologies and applications in language teaching, and new horizons in the discipline, including the possibilities offered by Artificial Intelligence.