This article updates the authors' 1990 review on the attention system of the human brain, integrating recent advancements in behavioral, systems, cellular, and molecular approaches. The original framework, which divided attention into three networks—alerting, orienting, and executive—has been elaborated and expanded. New networks have been identified, and methods for understanding interactions between them have been developed. The role of genetic variations in individual differences in network efficiency has been explored, and the development of attention in childhood has been examined. The article also discusses the evolution of attention networks, the impact of environmental factors, and the potential for training to enhance attentional functions. The authors highlight the importance of these advancements in understanding pathology and developing interventions.This article updates the authors' 1990 review on the attention system of the human brain, integrating recent advancements in behavioral, systems, cellular, and molecular approaches. The original framework, which divided attention into three networks—alerting, orienting, and executive—has been elaborated and expanded. New networks have been identified, and methods for understanding interactions between them have been developed. The role of genetic variations in individual differences in network efficiency has been explored, and the development of attention in childhood has been examined. The article also discusses the evolution of attention networks, the impact of environmental factors, and the potential for training to enhance attentional functions. The authors highlight the importance of these advancements in understanding pathology and developing interventions.