The Data Handbook was originally published in 1992 by Spyglass, Inc., a Savoy, Illinois-based visualization software publishing company who markets their products primarily to scientists and engineers. This "Handbook" was authored by Brand Fortner, one of the founders of Spyglass, and it was his experience in working with large amounts of numerical data that provided the underpinnings for this work. The second edition contains updated and corrected materials, and includes 100 pages of new material in Part IV on Data Formats. Numerous journal reviews of the first edition have pointed out the value of the book. A structured array of data sets will be available online via the TELOS Web site, www.telospub.com, which will provide users with direct digital access to information they might need in working through the book.