Next-generation sequencing (NGS) has revolutionized both clinical practice and biomedical research by providing rapid, highly accurate, and high-throughput genomic analysis. This review explores the technological progression of NGS, its contribution to mapping human genomic diversity, and its growing utility in areas such as precision medicine, oncology, pharmacogenomics, the diagnosis of rare disorders, and clinical decision support. By detecting single nucleotide variants, copy number changes, structural variations, and complex genomic rearrangements, NGS has deepened our understanding of disease heterogeneity and facilitated the creation of targeted treatment plans. In the field of oncology, the adoption of NGS has improved tumor classification, enabled therapies tailored to specific genetic profiles, and allowed for real-time monitoring via circulating tumor DNA analysis. 
 In pharmacogenomics, NGS has improved drug response prediction by identifying both common and rare variants affecting drug metabolism. Additionally, its application in rare diseases has shortened diagnostic odysseys and accelerated novel gene discovery. Despite challenges related to data interpretation, ethical governance, regulatory oversight, and data management, continuous technological innovation and multi-omics integration are strengthening the clinical utility of NGS. Collectively, NGS serves as a foundational pillar of personalized medicine, shaping a more predictive, preventive, and precision-oriented healthcare paradigm.