A Survey of Query Auto Completion in Information Retrieval

In information retrieval, query auto completion (QAC), also known as type-ahead and auto-complete suggestion, helps users to formulate their query when they have an intent in mind but not a clear way of expressing this in a query. This monograph surveys this research. It focuses on summarizing the literature on QAC and provides a general understanding of the wealth of QAC approaches that are currently available.