Liquid biopsy represents a transformative shift in cancer diagnostics, offering a minimally invasive approach to detect, monitor, and understand malignancies through the analysis of circulating biomarkers. This book explores the clinical and research potential of circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and exosomes-key components in the liquid biopsy landscape. It highlights growing role of liquid biopsy in precision oncology in oral cancer diagnostics.