This open access book explores the history, production, and certification of reference materials for essential parameters in oceanography and provides a comprehensive understanding of them to readers. Because inorganic macro-nutrients, salinity, dissolved oxygen, and carbonate system parameters, including dissolved inorganic carbon, total alkalinity, and pH, are essential parameters in oceanography, they can be used to define biogeographic provinces, monitor ocean health, and detect decadal-scale oceanic climate changes. Without reference materials for these parameters, it would be difficult to produce reliable data sets or long-term baseline studies that are required to verify global change and oceanic stability.