Book excerpt: This book, written by two HP web services experts, is the authoritative guide to the UDDI registry technology in both Sun's J2EE and Microsoft's .NET environments. Registries are a cornerstone of web services. This book examines registries in detail, discussing the value proposition, providing hands-on examples for registering and discovering web services within XML-based registries, and including a survey of the registry competitive landscape. It covers all aspects of the service life cycle and walks readers through deploying a private UDDI registry. The book focuses on UDDI and to a much lesser extent, ebXML, and refers to supporting web services technologies where appropriate. UDDI (Universal Description, Discovery, and Integration) is an XML - based registry for businesses worldwide to list themselves on the Internet. Its ultimate goal is to streamline online transactions by enabling companies to find one another on the Web and make their systems interoperable for e-commerce. UDDI is often compared to a telephone book's white, yellow, and green pages.