This document discusses cloud computing and its applications in libraries. It defines cloud computing as a model that enables on-demand access to shared computing resources like networks, servers, storage, and applications via the internet. The document outlines different types of cloud computing based on service models like IaaS, PaaS, and SaaS and deployment models like private, public, hybrid and community clouds. It discusses advantages like reduced costs and disadvantages like loss of data control. The document concludes that cloud computing can help libraries reduce costs and focus on services while providing anytime access to shared resources.