Free Software (FS), a concept developed by Richard Stallman in the 1980s, has served as a foundation for important and related movements that have become possible because of the Internet. The most important of these has been the Open Source Software (OSS) movement. OSS, a concept rooted in software methodology and analyzed by Eric Raymond, broke from the FS ethos in 1998. This paper will compare FS and OSS, examining their histories, their philosophies, and development. It will also explore important issues that affect the ethical interests of all who use and are subject to the influences of software, regardless of whether that software is FS or OSS. We will argue that the distinction between FS and OSS is a philosophically and socially important distinction.To make this point we will review the history of FS and OSS with a particular emphasis on four main people: Richard Stallman, Linus Torvalds, Eric Raymond, and Bruce Perens. In addition, we will review the differences between GNU General Public License (GPL) version 2 (v2) and the current draft of the GPL version 3 (v3), and the related controversy in the OSS community. The GPL is the primary mechanism used by the software community to establish and identify software as free software. In section 10.3, we will examine the motivation and economics of OSS developers. We will review issues of quality with respect to OSS, autonomy of OSS software developers, and their unusual professional responsibilities. The final important issue we address is consideration of OSS as a public good.