  The ever-increasing quality and complexity of astronomical data underscores
the need for new and powerful data analysis applications. This need has led to
the development of Sherpa, a modeling and fitting program in the CIAO software
package that enables the analysis of multi-dimensional, multi-wavelength data.
In this paper, we present an overview of Sherpa's features, which include:
support for a wide variety of input and output data formats, including the new
Model Descriptor List (MDL) format; a model language which permits the
construction of arbitrarily complex model expressions, including ones
representing instrument characteristics; a wide variety of fit statistics and
methods of optimization, model comparison, and parameter estimation;
multi-dimensional visualization, provided by ChIPS; and new interactive
analysis capabilities provided by embedding the S-Lang interpreted scripting
language. We conclude by showing example Sherpa analysis sessions.
