Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Preboot eXecution Environment (PXE, pronounced pixie and also known as Pre-Execution Environment) is an environment to boot computers using a network interface independently of data storage devices (like hard disks) or installed operating systems. PXE was introduced as part of the Wired for Management framework by Intel and is described in the specification (version 2.1) published by Intel and Systemsoft on September 20, 1999. It makes use of several network protocols like Internet Protocol (IP), User Datagram Protocol (UDP), Dynamic Host Configuration Protocol (DHCP) and Trivial File Transfer Protocol (TFTP) and of concepts like Globally Unique Identifier (GUID), Universally Unique Identifier (UUID) and Universal Network Device Interface and extends the firmware of the PXE client (the computer to be bootstrapped via PXE) with a set of predefined Application Programming Interfaces (APIs). The term PXE client only refers to the role that the machine takes in the PXE boot process.