The System.Globalization namespace contains classes that define culture-related information, including the language, the country/region, the calendars in use, the format patterns for dates, currency, and numbers, and the sort order for strings. These classes are useful for writing globalized (internationalized) applications. Classes like System.Globalization.StringInfo and System.Globalization.TextInfo provide advanced globalization functionalities, such as surrogate support and text element processing.