Here is a thorough and authoritative guide to the latest version of the S language and to its programming environment, the premier software platform for computing with data. Programming with Data describes a new and greatly extended version of S, and is written by the chief designer of the language. The book is a guide to the complete programming process, starting from simple, interactive use and continuing through ambitious software projects. S is designed for computing with data - for any project in which organizing, visualizing, summarizing, or modeling data is a central concern. Its focus is on the needs of the programmer/user, and its goal is "to turn ideas into software, quickly and faithfully." S is a functional, object-based language with a huge library of functions for all aspects of computing with data. Its long and enthusiastic use in statistics and applied fields has also led to many valuable libraries of user-written functions. The new version of S provides a powerful class/method structure, new techniques to deal with large objects, extended interfaces to other languages and files, object-based documentation compatible with HTML, and powerful new interactive programming techniques. This version of S underlies the S-Plus system, versions 5.0 and higher. John Chambers has been a member of the technical staff in research at Bell Laboratories since 1966. In 1977, he became the first statistician to be named a Bell Labs Fellow, cited for "pioneering contributions to the field of statistical computing." His research has touched on nearly all aspects of computing with data, but he is best known for the design of the S language. He is the author or co-author of seven books on S, on computational methods, and on graphical methods; and he is a Fellow of the American Statistical Association and the American Association for the Advancement of Science.