Grounded theory is a qualitative research method involving the discovery of theory through the analysis of data. It was developed by sociologists Barney Glaser and Anselm Strauss, who felt researchers needed a method to move from data to theory to develop new, contextualized theories. The method involves collecting data through various means, then coding and categorizing it to identify concepts and their relationships. Researchers constantly compare data and emerging concepts through steps like theoretical sampling and saturation to build a theory grounded in the data.