Cloud Computing is both a trend and technology to deliver software (SaaS) and hardware as a service, not as a product. It involves a centralized data center, virtual server space, and secure transfer of data over the internet. The alleged advantages of cloud computing include low cost to own, agile updates, and openess, to name a few. Library system vendors are now beginning to offer cloud computing options. For instance, Ex Libris will release Alma early next year. It is an Integrated Library System with a discovery layer based on cloud computing. Amazon's Elastic Compute Cloud (EC2) also offers virtual servers for cloud computing and charges customers by the hour; other vendors offer similar services. If this phenomenon continues for the next several years, librarians will face the decision of whether to move into cloud computing sooner or later. This presentation will explain cloud computing in simple, easy-to-understand language. The discussion will focus on the pros and cons of moving into cloud computing for libraries.