From its beginnings as a descriptive framework for structure determination experiments, CIF has grown to be a powerful framework for many aspects of crystallographic practice. It describes or is actively used in raw data collection (such as diffraction images), data reduction (e.g. as structure factors or Rietveld profiles), structure solution and refinement, and the publication, database curation and visualisation of crystal and molecular structures. Although not the only format in common use in the structural sciences, it is central to structure determination of small-unit-cell and macromolecular structures, and its ontologic approach informs the best practice of information and data handling throughout crystallographic researches.