Businesses today increasingly rely on Information Technology (IT) to function effectively. Traditional workloads, such as inventory management and transaction processing, are being joined by an array of other applications, such as payroll and attendance reporting and customer relationship management (CRM) software. Additionally, companies have increasingly named e-mail among the top mission-critical applications in a number of recent studies. Because your business places so much demand on its applications, you need an enterprise server platform that will provide reliable operation, offer scalable headroom, and, of course, be secure. Moreover, the server platform must also be manageable, interoperable with industry standards and legacy systems, and support your goals in reducing your total cost of ownership (TCO), by doing more with less. Windows Server 2003 R2 Enterprise Edition meets those needs with enhanced reliability through failover clustering and fault-tolerant configurations, scalability up to eight processors, and 1 TB (terabyte) of RAM. Building on the dependable security of the Windows Server™ family, Windows Server 2003 R2 Enterprise Edition supports enterprise-level security scenarios, such as more scalable Remote Authentication Dial-in User Service protocol (RADIUS) services and virtual private network (VPN) quarantine. Finally, Enterprise Edition is a highly manageable platform, which contributes to reliable and secure operation. As the business moves commerce and other operations to the Internet, the demand for these applications, both Web-based and back-end processing systems, grows to require 24/7 support. Windows Server 2003 R2 Enterprise Edition is the recommended edition for supporting mission-critical enterprise applications, such as databases, e-mail, business applications, and branch office management. This paper will look at the benefits of using the Windows Server R2 family, the application of Enterprise Edition features to mission-critical applications, and drill down on the features found only in Enterprise Edition to explain their benefits.