Thomas Baier and Erich Neuwirth High-Level Interface Between R and Excel **************************************** Spreadsheet programs in general and Microsoft Excel in particular implement a very special paradigm of computing: automatic creation of dependency structures for calculation, and automatic recalculation when input values change. This is rather different from the usual model of batch processing underlying most statistics software, e.g. R. Since some time now, a COM server implementation for R has been available. As a more recent development, R can also act as COM client, using Excel as a server. So we can either think of R as an extension of Excel, or of Excel as a utility program (and data editor) for R. We will discuss the differences between these 2 approaches, and their relative merits under different circumstances. This will be done by showing examples of applications implementing these rather different models for statistical computation. Emphasis will be more on the philosophy and style of statistical analysis than on technical implementation details.