Volume 1, Issue 1 (2021) of Optimization in Applied Machine Learning highlights the latest advancements and practical applications of machine learning in solving real-world challenges. This issue features cutting-edge research on optimization algorithms, robust machine learning models, and their implementations across diverse fields such as healthcare, finance, transportation, and energy. With a focus on innovation and practical impact, the articles in this edition provide valuable insights for researchers, practitioners, and industry professionals seeking to enhance the efficiency and effectiveness of machine learning systems.