Single-molecule detection is a technique used to observe and analyze individual molecules rather than bulk samples. This method allows scientists to study the properties and behaviors of specific molecules, providing insights into biological processes, chemical reactions, and material properties at an unprecedented level of detail. This approach often employs advanced technologies such as fluorescence microscopy or atomic force microscopy to visualize and measure single molecules. By detecting individual molecules, researchers can gain valuable information about their interactions, dynamics, and functions, which is crucial in fields like biochemistry, nanotechnology, and pharmaceutical research.