This document provides an introduction to Linux, including: 1. It defines Linux as a UNIX-like operating system that is multi-user, multitasking, and runs on multiple hardware platforms. 2. It discusses the history of Linux, including its origins in 1991 when Linus Torvalds developed the initial Linux kernel version 0.0.1 at the University of Helsinki. 3. It notes that today Linux is used widely for computing platforms like PCs, supercomputers, and more, and provides graphical user interfaces as well as command line interfaces.