But discovery's external simplicity hides a complex system running in the background, making decisions for our users. And it is the rare user that questions these decisions. As Sherry Turkle (1997) observed, users approach complex systems like search engines at “interface value.” Since the interface is simple, they are content to assume that the underlying mechanism that makes them work is also simple. They are often unaware that complex algorithms help determine what results are shown and what results are excluded. As library search in particular has become simpler, the complex workings of our search tools have, like Google's, receded into a black box. As Tim Sherratt (2016) reminds us “it's not just the simplicity of that single search box, it's our faith that search will just work.”