National Language Support (NLS) is a set of features that enable a software product to function properly in every global market for which the product is targeted. The SAS System contains NLS features to ensure that SAS applications can be written to conform with local language conventions. SAS provides NLS for data as well as for code under all operating environments and on all hardware, from the mainframe to the personal computer. This guide provides comprehensive conceptual information and detailed syntax for all SAS language elements that contain NLS properties, including information about NLS concepts; data set options; formats, informats, and functions; procedures; system options; commands and statements; and values for locale, encoding, and transcoding. The SAS 9.1 National Language Support (NLS): User's Guide consolidates all information about NLS that was previously contained in multiple SAS documents. This title is also available online. The audience for this document will already have expertise in the particular SAS product that requires NLS compliance. Supports releases 9.1 and higher of SAS software.