In July 2002, BEA, IBM, and Microsoft released a trio of specifications designed to support business transactions over Web services. These specifications, BPEL4WS, WS-Transaction, and WS-Coordination, together form the bedrock for reliably choreographing Web services-based applications, providing business process management, transactional integrity, and generic coordination facilities respectively. The value of BPEL4WS is that if a business is the sum of its processes, the orchestration and refinement of those processes is critical to an enterprise’s continued viability in the marketplace. Those businesses whose processes are agile and flexible will be able to adapt rapidly to and exploit new market conditions. This article introduces the key features Business Process Execution Language for Web Services, and shows how it builds on the features offered by WS-Coordination and WS-Transaction to support the reliable orchestration of business processes.