This study focused on front-line supervisors in a union shop, steel-production plant and how they learn to successfully negotiate their role with in the corporation's division of labor. Negotiating their role means continued practice in how issues of standpoint, agency, power, oppression, habits, knowledge, related business concerns, mediating instruments integrity, etc, intersect in ways that shape, inform, and guide how one engages, conducts, discusses, confers, consults, bargains, agrees, and settles the various issues bounded within the workplace environment. Six front-line supervisors were interviewed and observed in their work-environment over a four month period. Cultural Historical Activity Theory (CHAT) was used as the analytical framework that informed data analysis. The following research questions guide this study; (1) What shapes and informs front-line supervisors learning? (2) What do front-line supervisors draw upon to develop and use supervisory skill? (3) How can informal instances of learning be empirically described in light of the full, complex range of artifacts, interactions, and shop-floor situations? Cultural Historical Activity Theory provided the comprehensive and exhaustive framework allowing for analyzing both the manifest and latent shop-floor processes. The structure provided by the triangular diagrams and the associated diagrams detailing multiple ones provided the opportunity to maintain a conscious effort regarding all the data. Analyzing how front-line supervisors addressed and resolved permitted me to empirically describe how they experienced learning. It permitted investigating the hidden world of front-line supervisors learning lives in respect to their accessing and grasping the latent aspects related to the division of labor, the unspoken rules, and the development and use of mediating instruments. Front-line supervisors drew upon their ability to convert primary contradictions into peripheral ones and for generating mediating instruments for future use through addressing the present contradictions. They also drew upon their ability to use the artifacts in the three way of mediation. They were using an artifact as designed, using an artifact through appropriation of an existing one, and by creating new mediating artifacts. The specific mediation employed rises from their access to and grasp of the underlying conditions as well as the latent shop-floor aspects. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]