Abstract: The shifting landscape of collections development and management, in conjunction with changing staffing models and priorities, has required an evolution of selection responsibilities at the University of Toronto (U of T). An administratively complex library system with over 40 libraries and three campuses serving over 88,000 students, significant portions of the University of Toronto Libraries (UTL) collections were historically built by selectors in the centralized Collection Development Department. Over the past decade, the model has evolved from a single individual selecting for all physical and applied sciences to many selectors, and of engineering and computer science disciplines have finally moved to a fully dispersed model where liaisons in the Engineering & Computer Science Library (ECSL) select for their liaison areas. Historically at the larger U of T Libraries, selection and liaison duties have been separate roles, ostensibly to let selectors and liaisons focus on developing the expertise and experience for their specific role. Over time, staffing levels at Engineering and Computer Science Library (ECSL) and librarian interest have necessitated a shift to a more distributed model for selection. In this paper, the authors will discuss how selection training has evolved over the years to become a robust program that includes ongoing mentorship and support, a new system-wide Collections Community of Practice initiative, and growing selector empowerment and capacity building in e-resource management and assessment through the resource lifecycle. As none of the current ECSL selectors were hired into their positions with selection duties but have had those duties added as the staffing model and requirements of the ECSL has changed, training and mentorship has become an important step in creating and maintaining the high-quality collections on which U of T prides itself. The paper will also look at the experience of the engineering and computer science librarians taking on selection for their liaison areas and the benefits and challenges of adding on the extra work and responsibility. The drawbacks and rewards of dispersing selection more generally will be discussed, as well as the mentorship and feedback in terms of collections philosophies as more experienced selectors train and mentor their colleagues new to this role.