This chapter provides a quick reference to all the datatypes the W3C XML Schema defines. Each datatype is listed along with its RELAX NG datatype parameters. The list corresponds to the W3C XML Schema facets available for the datatype, with the exception of the whiteSpace facet (which isn’t supported by RELAX NG). It also provides information about what the facets represent and how they do it. For the secondary datatypes (the W3C XML Schema builtin types that are derived from another builtin type), the synopsis shows the formal definition of the type using W3C XML Schema syntax. Examples are given for all these datatypes.