Collection development is at the core of the work of children's librarians, an ongoing activity that shapes collections as well as library spaces, services, programming, and communities. The process of collection development includes the consideration of several factors that impact the evaluation, selection, and acquisition of books available for children. This research examined the phenomenon of children's librarians' collection development practices during the period of 2019 to 2021, as well as influential factors and the impact of children's librarians' identities and views into the decision-making and selection process. Using Gramsci's Hegemony and Patricia Hill Collins's Critical Race Theory Domains-of-Power frameworks, this study reviewed if and how current collection development practices enact, replicate, challenge, or critique white hegemony in libraries and children's librarians as one of the functionaries of such white hegemonic structures. This multiple case study qualitative research focused on five U.S. public library sites, where data was collected via semi-structured interviews with children's librarians, library collection development policies, and picture book children's collection samples. Factors like the U.S. political landscapes, COVID-19 pandemic, George Floyd's murder and Black Lives Matter protests, community and patron requests, book reviews in journals, book awards and book lists, along with children's librarians social geographies, childhoods, and identities were identified as influential to collection development practices. The study presented IBPOC and white women children's librarians as participants in collection development, but findings show the presence and power of whiteness, womanhood, and internalized oppressions in children's librarianship. Research results assisted in viewing and situating the children's library collection as part of a larger ideological and structural discourse, and the role of individuals and communities in the systems of power. By bringing Critical Race Theory and Gramsci's Marxism into the field of children's librarianship, it contributes to the body of work done in the field and encourage more studies that will explicitly use these frameworks to move beyond diversity by addressing racism, power, and dominant ideologies and their presence in the macro and micro levels in society, libraries, and children's rooms. Although dismantling white supremacy and dominant ideologies is an ongoing and challenging process, this work encourages children's library workers to be mindful, to reflect, to critique, to challenge their work and practices as we move towards collective liberation. [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.]