This book constitutes the refereed proceedings of the 13th International Conference on Rough Sets, Fuzzy Sets, Data Mining, and Granular Computing, RSFDGrC 2011, held in Moscow, Russia in June 2011.
The 49 revised full papers presented together with 5 invited and 2 tutorial papers were carefully reviewed and selected from a total of 83 submissions. The papers are organized in topical sections on rough sets and approximations, coverings and granules, fuzzy set models, fuzzy set applications, compound values, feature selection and reduction, clusters and concepts, rules and trees, image processing, and interactions and visualization.

Alarms are being sounded around the globe over the increasing commercialization of public knowledge for private profit. Whether you are a farmer, a medical patient, or a library user, these developments impact your daily life. Knowledge privatization holds growing sway over the choice of the foods you eat, the medicine you take, the software you use, the music you hear, and even the flowers you plant in your own backyard. This is the result of a world where plant seeds have become subject to patents, medical research is overseen by pharmaceutical giants, universities are beholden to corporate funders, and indigenous knowledge is expropriated. The good news is that people are fighting back, working to create spaces where humanity's knowledge can be reclaimed and shared for the public good. Composed of fifteen essays from seventeen writers, ranging from academics to farmers to indigenous knowledge keepers, Free Knowledge is a book on the front lines of the shared project of creating and protecting our Knowledge Commons.