Stallman is known internationally as the creator of the GNU operating system and cofounder of the Free Software Foundation. In this collection, he provides an accessible guide to the philosophy that inspired his cause. Stallman also takes a critical look at how businesses abuse copyright law and patents as they apply to computer software applications. He explains how these actions damage our society and encroach on our freedoms. Part 1, "The GNU Project and the Free Software Foundation," offers a historical perspective, as well as an introduction, to the philosophy of free software (i.e., free as in "free speech, not free beer"). Part 2, "Copyrights, Copylefts and Patents," explores the legal aspects of free software, laying out the mission of the free software movement and discussing its long-term goals. Part 3, "Creating a Free Society," focuses on the importance of free software in our society and presents helpful examples. Part 4 comprises licenses that developers will find useful in making the programs they create accessible to the widest possible audience, as free software that can be redistributed and changed legally under the terms presented. The text gives more insight into Stallman's thought processes than does Sam Williams's biography, Free As in Freedom, a complementary work that relies more on interviews with Stallman and his associates. This important collection by a software visionary is recommended for larger public and academic libraries.