S is the language that underlies S-PLUS and the R language -- an open source version available from the R Project. The tutorials area includes a non-technical introduction to the S language, and "A Guide for the Unwilling S User" -- a brief document to help new users get started using S productively.
S Poetry is a book that is geared towards those who plan to program in S. However, there are some parts that can be of use to others:
- The glossary explains words that involve computing and statistics as well as S. It can be useful to someone who knows one subject, but not the other. Also it is useful to those who know both subjects, but for whom English is not a native language. Emphasis is put on words that have more than one meaning.
- The first chapter, called "Essentials", gives a grounding in the language and is of interest even to those who don't envision themselves programming.
- In addition, there is a collection of S functions and other objects. These offer functionality that can be of interest even if you don't care about the book.