The document introduces Windows Technical Preview, an early pre-release build of the next version of Windows. It discusses four key ways this preview differs from previous releases: it is a subset of the full build, bits are released earlier in development, it expects more user feedback, and it uses ongoing development-feedback cycles. It then explains how to enroll in the Windows Insider Program to access the preview builds and provides an overview of new features in the Technical Preview like the return of the Start menu and windowed apps.