The document discusses grid computing, which involves solving complex problems using distributed computer resources and coordination of jobs and data across different administrative domains, and outlines some of the major challenges in managing and scheduling resources and jobs across grids. It also provides an overview of the Globus Toolkit, a widely used set of open source software tools for building grids, describing its architecture, core components for resource management, security, and information services, and some applications and middleware systems that are built using Globus.