Underlying the graphical user interface of SPSS 9.0 is a command syntax that enables production-mode operation of the software and gives access to complex file definitions and less commonly used specifications on statistical procedures. The syntax for all commands in SPSS Base, including the new interactive graphs, is presented in this Guide. Following an introduction to the "universal" features of the command language, commands are presented in alphabetical order with detailed descriptions of each specification and many examples. The book includes both a subject index and an index to all keywords in the language.