Despite all the data that retailers and e-tailers can now gather about point-of-purchase information, buying patterns, and customers' tastes, they still haven't figured out how to offer the right product, in the right place, at the right time, for the right price. Most retailers largely ignore the billions of bytes of customer data stored in their databases-or they handle that information incorrectly. As a result, they don"t adequately supply what consumers demand. But some retailers are moving profitably toward what the authors call "rocket science retailing"- a blend of traditional forecasting systems, which are largely based on the gut feel of employees, with the prowess of information technology. Marshall Fisher, Ananth Raman, and Anna Sheen McClelland recently finished surveying 32 retail companies in which they tracked their practices and progress in four areas critical to rocket science retailing: demand forecasting, supply-chain speed, inventory planning, and data gathering and organization. In this article, the authors look at some companies that have excelled in those four areas and offer some valuable advice for other businesses seeking retailing perfection. In particular, the authors emphasize the need to monitor crucial metrics such as forecast accuracy, early sales data, and stockouts-information that will help retailers determine when to tweak their supply-chain processes to get the right products to stores at just the right time. The authors discuss the information technologies now available for tracking that information. They point out the flaws in some reporting and planning systems and suggest alternate methods for measuring stockouts, inventory, and losses.