Single particle biophysics is a subfield of biophysics dedicated to the study of the physical properties, dynamics, and interactions of individual biological molecules, complexes, or assemblies. This research approach focuses on observing, manipulating, and characterizing single entities to circumvent ensemble averaging, thereby revealing heterogeneity, transient states, and detailed mechanistic pathways that are often obscured in bulk measurements. Its significance lies in providing fundamental insights into the molecular mechanisms underlying biological processes at the nanoscale, contributing to a deeper understanding of molecular function, regulation, and disease.