Betty Neumann's system model provides a holistic perspective for nursing and focuses on how clients respond to stressors. It views individuals as unique systems composed of biological, psychological, socio-cultural, and developmental variables that interact with internal and external environments. The model outlines primary, secondary, and tertiary prevention interventions to help client systems maintain wellness when faced with stressors. It has influenced nursing practice, education, and research by conceptualizing health as harmony within the client system and defining nursing's role in assisting clients through various stages of reaction to stressors.