Faye Glenn Abdellah significantly influenced nursing theory by shifting the profession's focus from disease-centered to patient-centered care, emphasizing the holistic needs of patients. She developed a typology of 21 nursing problems covering basic, sustenal, remedial, and restorative care needs, along with a systematic approach for identifying and addressing patient issues. Abdellah's work laid the foundation for improved nursing education and practice, advocating for a comprehensive understanding of individual patient needs.