Librarians have a professional responsibility to protect the right to access information free from surveillance. This right is at risk from a new and increasing threat: the collection and use of non-personally identifying information such as IP addresses through online behavioral tracking. This paper provides an overview of behavioral tracking, identifying the risks and benefits, describes the mechanisms used to track this information, and offers strategies that can be used to identify and limit behavioral tracking. We argue that this knowledge is critical for librarians in two interconnected ways. First, librarians should be evaluating recommended websites with respect to behavioral tracking practices to help protect patron privacy; second, they should be providing digital literacy education about behavioral tracking to empower patrons to protect their own privacy online.