Book excerpt: The Oxford Guide to Financial Modeling is accompanied by a companion web site that serves as an interactive workbook designed specifically for the book. This site is simple to use yet exceedingly robust with regard to its technological efficiency and purposeful usability. It is designed to further enhance understanding of the use and applications of the models referred to in the book and it is accessible free of charge at www.thomasho.com. This on-line workbook and resource tool contains more than 95 downloadable Excel models. The models provide clear expositions of the mathematical formulations and can be used along with the book. The companion web site is rich with a plethora of research and analytic tools designed for "doing finance" on-line.