Windows PE 2.0 for Windows Vista Overview --https://technet.microsoft.com/en-us/library/cc507857.aspx
Microsoft Windows Preinstallation Environment (Windows PE) 2.0 provides powerful preparation and installation tools for the Microsoft Windows Vista operating system. With Windows PE, you can start a subset of Windows Vista from a network or removable medium, which provides network and other resources necessary to install and troubleshoot Windows Vista. This document is an introduction to Windows PE, its capabilities, and its improvements over earlier pre-installation technologies.
Windows PE Technical Reference | Technet --https://technet.microsoft.com/en-us/library/cc749538.aspx
Windows Preinstallation Environment (Windows PE) is a minimal operating system designed to prepare a computer for Windows installation. It can be used to start a computer with no operating system, to partition and to format hard drives, to copy disk images, and to initiate Windows Setup from a network share. Reference: What is Windows PE?, How Windows PE Works, Windows PE Tools and Settings.