Publisher Summary The digitally accessible information about an object can be called its information shadow. Nearly all industrially created objects have rich information shadows, even if those shadows are invisible to their owners and users. Everyday objects have been separated for a long time from their information shadows. The complexity of finding, organizing, and accessing this information divided the world of objects and the world of information shadows. Even if accessible through a computer, information shadows were unavailable when they could provide the most value in choosing between different products to buy, or in figuring out how to use a new tool. For example, barcodes are not human-readable. So for a long time, only those with barcode readers and access to specialized databases could use them, which basically only included retailers and their employees. Even then the kinds of data available to retailers were limited. Standard Universal Product Code barcodes identify classes of products, not individual things. Moreover, there is no universal database of barcodes. So a retailer’s information about a given object is limited to data it has bought or generated on its own. Typically, like the early Borders Books system, retailers only keep enough information around to price items and order more.