Email has been an essential communication medium for many years and the information accumulated in our mailboxes has become valuable for all of our personal and professional activities. As our mailboxes grow, so does the need for the development of new effective approaches to information finding in this repository. For years, researchers have been developing interfaces, models and algorithms to facilitate search, discovery and organization of email data. In this survey, the authors bring together these diverse research directions by providing both a historical background as well as a comprehensive overview of the recent advances in the field. In particular, they lay out all the components needed in the design of a privacy-centric email search engine. They also go beyond search, presenting recent work on intelligent task assistance in email. Finally, they discuss some emerging trends and future directions in email search and discovery research.