This document discusses CI/CD (Continuous Integration/Continuous Delivery). It begins by defining CI as integrating code changes frequently using automated builds and tests. CD is defined as taking CI further by making sure code changes can be released to production at any time by having multiple environments. The document then provides a brief history of CI/CD concepts and tools. It discusses how CI works with version control systems and testing. Continuous Delivery is described as getting code to a releasable state while Continuous Deployment is automatically deploying all code changes. The document encourages using CI/CD practices as part of a DevOps approach with infrastructure as code.