Enterprise-class databases require database administrators (DBAs) to select a physical database design appropriate for the system. An important component of physical database design is selecting indexes. In data intensive applications such as decision support and data warehousing, choosing the right set of indexes is crucial for performance. This chapter describes the Index Tuning Wizard: a Microsoft SQL Server 7.0 wizard that automates the challenge of index selection, while achieving performance competitive with that of indexes handpicked by DBAs.