This collection of notes introduces the scientific study of resilience in children facing adversity like trauma, disasters, and war. It outlines the origins of this research, tracing its evolution through four distinct waves, from focusing on individual traits to examining complex, multilevel systems. Key concepts, such as the definition of resilience as positive adaptation and the importance of protective factors and early intervention, are highlighted. The notes also summarize early landmark studies that significantly contributed to understanding how children overcome challenges and emphasized the dynamic nature of resilience across various contexts. Ultimately, the sources provide a foundational understanding of resilience science, its theoretical underpinnings, and its practical applications for supporting vulnerable children.