The document provides a history and overview of .NET and .NET Core. It discusses: - The origins and evolution of .NET from 2000-2017, including key releases and frameworks. - How .NET Core was introduced in 2016 as a cross-platform, open source and modular successor to .NET Framework focused on containers and microservices. - The architectural differences between .NET Framework and .NET Core, with Core being optimized for Linux, macOS, Docker and cloud-based applications. - Microsoft's increasing commitment to Linux and open source in recent years.