Book excerpt: "We regularly read and hear exhortations for women to take up positions in STEM. The call comes from both government and private corporate circles, and it also emanates from enthusiasts for free and open source software (FOSS), i.e. software that anyone is free to use, copy, study, and change in any way. Ironically, rate of participation in FOSS-related work is far lower than in other areas of computing. A 2002 European Union study showed that fewer than 2 percent of software developers in the FOSS world were women. How is it that an intellectual community of activists so open in principle to one and all -a community that prides itself for its enlightened politics and its commitment to social change - should have such a low rate of participation by women? This book is an ethnographic investigation of efforts to improve the diversity in software and hackerspace communities, with particular attention paid to gender diversity advocacy"--