This thesis introduces the study of inmate marginalia as a method for understanding inmates’ uses of texts in prison libraries and for understanding the motivations for these uses. Marginalia are the notes, drawings, underlining, and other markings left by readers in the texts with which they interact. I use the examples of the Talmudic projects to set a precedent for the integration of marginal discourses into the central discourse of society. Next, I discuss the arguments surrounding the use of texts in prison libraries, including an outline for an ideal study of inmate marginalia. Finally, I discuss the findings of my on-site research at four prison libraries in Washington State. After scanning evidence of marginalia from forty-eight texts, a relatively small sample, I divided the marginalia by gender of facility, genre of text, address of the marginalia, and type of marginalia and found statistically significant correlations (p < 0.05) between gender and genre, gender and address, gender and type, and genre and type. However, while these correlations are statistically weak and require further investigation, the statistically significant correlations indicate the potential for integrating inmate marginalia studies into the scholarly discussions regarding inmates’ interactions with texts in prison.