Microsoft SQL Server has evolved over several versions since 1989. It started as a proprietary system but later became Windows-only. There are different editions for various workloads and needs, from express editions for small uses to enterprise editions for large organizations. SQL Server services can be instance-specific, running one service per instance, or instance-unaware. Administrators have several tools for managing SQL Server, including SQL Server Management Studio for database management and SQL Server Profiler for monitoring queries.