The document provides an overview of web services and their evolution from traditional siloed applications to today's interconnected standards-based services. It begins by describing how early applications operated independently with isolated data and functionality. It then discusses the rise of distributed computing technologies that allowed some inter-application communication but still lacked open connectivity. The document focuses on how web services standards like SOAP, REST, XML, and HTTP have enabled true interoperability and reusability across organizations and platforms. It provides examples of SOAP and REST usage and highlights some key web service specifications and standards.