I argue for three theses: T1 — Access to scientific knowledge can be used to reinforce existing scientific communities and sometimes generate new ones. T2 — Community can be used to generate scientific knowledge, patent reform, scientific research, medical diagnostics, and trade secrets and occasionally patents. T3 — On the spectrum from commons to semicommons to private property to anticommons, an anticommons can arise if a biotechnological asset is fuzzily defined. I defend these propositions against objection and establish the fertility of my account by considering intellectual property issues relating to synthetic biology. Along the way I present a new understanding of the public domain. I also pursue several projects that are interwoven throughout the Article. The analytic project shows how careful definitions yield a useful taxonomy of biotechnological assets and their holders. The normative project explains why we should endorse intellectual property rights in some biotechnological assets but not others. Finally, the thematic project establishes larger contrasts between different forms of community on the one hand and individualism on the other, and reveals how my understanding of the public domain yields a surer grasp of these contrasts and their roles in institutions of property.