Title: Statistical Computing using Common Lisp: Back from the Past, with a Twist. Abstract: We describe a general purpose system which supports research in statistical computing, using ANSI Common Lisp as its basis. This system provides limited support for XLispStat programs. The intention of the system is to provide a framework to study the impacts of model specification, object orientation, and modern computational tools on practical statistical analysis. The design will be contrasted to LispStat and S, with the hope for constructive criticisms to improve development directions. Open source Common Lisp implementations have greatly matured since 1990, when CommonLispStat was made availabe. Reasons which drove the selection of Common Lisp are discussed, and why it was selected instead of a possibly more interesting choice, Python (which the author had proposed for such a task during DSC 1999 conference). Anthony (Tony) Rossini