Introduction W elcome to  Cloud Services For Dummies,  IBM Limited  Edition .  Whether public, private, or hybrid, cloud  computing is becoming an increasingly integral part of many  companies’ business and technology strategy. Cloud services  help companies turn IT resources into a flexible, elastic, and  self-service set of resources that they can more easily manage  and scale to support changing business needs. While many different delivery models for cloud computing  services exist, two foundational services are a requirement  for making cloud computing into a strategic part of an overall  computing infrastructure. These include Infrastructure as a  Service (IaaS) and Platform as a Service (PaaS). IaaS is the services that enable you to gain access to compute and storage  resources in an on demand model. PaaS is the services that sit  on top of IaaS and enable you to build applications to support  the business. No matter what your plan for your evolving IT infrastructure  may be, you can take advantage of these services in combination  with on-premises platforms to create flexibility for the business. Cloud computing serves different needs for different constituents within your organization. For business leaders, cloud computing  is a cost-effective way to leverage IT resources to prototype  and implement strategic change. For your IT organization, the cloud is a platform that allows it to be significantly more  proactive and responsive when it comes to supporting strategic business imperatives. While IT is leading the charge  in focusing on best practices that support the balanced use  of public, private, and data center resources — the emerging  world of hybrid computing — don’t lose sight of the fact that  cloud is just as much about business model transformation as it is about technology transformation. In fact, many companies find that the cloud helps to support increased collaboration between business and IT leaders enabling them  to more quickly adjust to changing market dynamics. These materials are the copyright of John Wiley & Sons, Inc. and any  dissemination, distribution, or unauthorized use is strictly prohibited.