Western blotting is a technique used to detect specific proteins in a complex mixture. It relies on the binding between a target protein and a probe, such as an antibody, to identify the target protein. The process involves separating proteins via SDS-PAGE gel electrophoresis, transferring them to a membrane, and using antibodies to detect the target protein band on the membrane. Western blotting is used to confirm diseases like HIV, mad cow disease, and some cases of Lyme disease.