This document provides an overview of .NET Core, ASP.NET 5, and Docker. It introduces .NET Core as a cross-platform version of .NET that allows side-by-side app versioning. ASP.NET 5 is the new version of ASP.NET that is modular and runs on .NET Core, supporting Web UI and APIs. Docker is a tool that allows packaging apps and dependencies into standardized containers to enable portable development environments. The document provides links for additional information on these topics and an example contact API project using these technologies on GitHub.