In August, the Unidata Program released the first version of a new, freely available visualization and analysis tool called the Integrated Data Viewer (IDV). The IDV brings together the ability to display and work with satellite imagery, gridded data (primarily from model output), and surface, upper air and radar data within a unified interface. It utilizes the emerging power of thematic data servers to easily connect users to a variety of web-based data sources through Thematic Real-time Environmental Data Distributed Services (THREDDS) using a variety of transfer protocols. Along with traditional sources of data, the IDV also integrates HTML and access to web servers and provides a unique HTML-based method for creating customized user interfaces. The IDV takes advantage of Java's WebStart technology to provide a seamless method for internet-based software distribution. Built entirely using the Java language and on top of the VisAD analysis and visualization package, the IDV provides many of the standard 2-D data displays that atmospheric scientists are used to, as well as 3-D views of the atmosphere. It allows users to interactively slice and probe the data to create cross-sections, profiles, animations and value readouts of multi-dimensional data sets. Using the power of the data model in VisAD, the IDV allows users to perform calculations on disparate data sets without having to convert from one format to another. With this underlying general data model, users in other geoscience disciplines (e.g., hydrology, oceanography) can use the IDV for analysis and visualization of their data sets. The IDV provides an XML-based mechanism for persistence, allowing for the ready sharing of interesting collections of data/visualizations, case studies and pedagogic materials over the Internet.