Dear SciPy users, PyDSTool is an integrated simulation, modeling and analysis package for dynamical systems (including ODEs, DAEs, maps, and hybrid systems) and scientific data. Building on SciPy classes, the package also supports symbolic expression processing, bifurcation analysis, and enhanced arrays for "index-free" and highly contextualized scientific data manipulation. Model building tools are provided, which use symbolic expression and hierarchical specification classes to ease the development and analysis of complex dynamical models. This includes automated compilation of symbolic representations of models into fast numerical code using enhanced legacy Fortran and C integrators for both stiff and non-stiff systems. A full overview and extensive user documentation is provided online at http://pydstool.sourceforge.net, and in the code itself. We have made a significant update in version 0.83 of PyDSTool, including added features for bifurcation/continuation analysis, symbolic expression manipulation and symbolic differentiation, use of Points as enhanced arrays, and the addition of support for external inputs to ODEs, maps, etc. (e.g., from experimental data sources). A full list of what's new is provided in the release notes on SourceForge. Thanks for your attention, Rob Clewley, Erik Sherwood, Drew LaMar, Dept. of Mathematics and Center for Applied Mathematics, Cornell University.