Both educators and researchers alike have a shared understanding that the mathematical identities, and perceptions of those identities, 6th and 7th grade students hold can influence their attitudes about their abilities as mathematics learners and doers. However, while identity work has gained popularity as a focus, researchers have yet to converge in terms of theoretical perspectives, definitions, or methodologies. This lack of convergence makes it difficult for the field to move in a concerted way. The body of work developed to capture data on student mathematical identity largely depends on the researcher -- particularly their definition of identity, the meanings and relationship among the components of the definition, and the way they choose to operationalize their definition. The purpose of this study is to add to the body of work researchers have already done while offering an approach for teachers to study their own middle school students' perceptions of their math identity in order to help build positive mathematical identity with classroom experiences. This study looked deeply at a diverse group of fifteen students who were in 6th and 7th grade through the use of a computerized survey followed by a clinical interview which ended with an engineered math task in order to get a clearer picture of their mathematical identities, perceptions of their identities, and what some of the factors were which led to the development of those identities. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]