Introduction
S is the language used by SPLUS and the R Project for Statistical Computing. S is a dataoriented language, and its strengths are in handling, analyzing, and presenting data.
Publisher’s information  Comments 

Data Analysis and Graphics Using R
by John Maindonald and John Braun August 1, 2003 Cambridge University Press ISBN 0521813360 
The book’s chapters are:

Introductory Statistics with R
by Peter Dalgaard 2002 Springer ISBN 0387954759 
This is an excellent introduction to using R for statistical analysis. The chapters are:
The ISwR package contains the data sets used in the book. 
Modern Applied Statistics with S
4th edition by W. N. Venables and B. D. Ripley August 2002 Springer ISBN 0387954570 
This book will not teach you statistical methods, but it will show you how to use statistical methods in the S environment using the open source R or the commercial SPlus software. 
Programming with Data: A Guide to the S Language
by John M. Chambers 1998 Springer ISBN 0387985034 
This is a guide to the S language used by SPlus and R. Some of the data analyzed as examples in the book comes from the SWafers Project. 
S Programming
by W. N. Venables and B. D. Ripley 2000 Springer ISBN 0387989668 
This is the authoritative guide to programming using the S language with SPLUS or R. 
Statistical Models in S
Edited by John M. Chambers and Trevor J. Hastie October 1, 1991 Chapman & Hall/CRC ISBN 041283040X 
This book provides coverage of how statistical models are specified and used with the S language. 