This thesis argues that in critical discussions of the history, mythology, and literary culture of California, the work of Los Angeles' bibliographers, antiquarians, collectors, librarians, and archivists has been hugely overlooked. Examining this group from the end of the nineteenth century through to the 1930s, this thesis proposes that their collection and assemblage of literary, historical, and visual material about California - often dubbed Californiana - points to a much wider and more systemic operation of regional mythology. Critically evaluating the history of these bibliographic institutions in Southern California, this thesis argues that the collecting and arranging of Californiana has been as influential to the construction of regional knowledge as the material itself. This thesis is concerned with both the literal and metaphorical shapes of history that these collections construct. Essentially, whilst there has been much scholarship on the mythography of Los Angeles and California history, this thesis proposes that how that history has been indexed and classified is as important and generative as what was written in its key historical and literary texts. This thesis is mostly about white elites of Anglo-American Southern California and how they framed regional history in line with their, at times, imperialist beliefs about the region's Spanish, Mexican, and Native American past. Whilst there is a substantial amount of academic literature on Anglo society, this thesis proposes that an entire strata of this culture has been relatively unexamined. This group of antiquarians, bibliographers and collectors were centrally concerned with cataloguing and arranging texts and historical data about the region and the conclusions we can draw from their work significantly advances our historical understanding of how the epistemology of American culture in the region operated, with all the social divisions that imperial lens implies. Anglo collecting and bibliographic culture developed in Los Angeles in a historical context radically different to, and much later than, other American cultures of regionalism. Reframing the region's past as antiquity, they collected and assembled Californiana in a setting of late-modernity in which the landscape of Southern California was rapidly changing. Through bookshop catalogues, the building and housing of library collections, the activities of the historical society, and the dimensions of private collections and personal archiving, this thesis posits that these works of artefact and document assemblage mediate between a romanticized past and a changing present, recreating narratives of Californian history and the way that history is experienced. The extension of this argument is that these institutions contributed to a historical optic and perspective on the region that would continue to be utilised by Anglo-American society throughout the twentieth century. The conclusions this thesis draws ensures it contributes to studies of American antiquarianism and modernity, bibliographic culture, regional history, material culture, and visual studies. This thesis builds on the recent critical directions in Los Angeles history that scholars such as William Deverell, D. J. Waldie, and Phoebe Kropp have advanced but it also reaches towards theoretical discourses proposed in fields not centrally connected to the study of California. In addition to the extensive work on Los Angeles and California, this thesis brings together theory in cultural history, studies of bibliographic culture, travel writing, and studies of visual culture. This theory helps to situate this thesis' archival case studies within a much broader and more dynamic critical context. Where these case studies have been written about, if they have been written about at all, they are restricted to local studies or limited discussions of the trades they were each a part of. But they deserve a much more expansive consideration: they each operated at the intersection between space and text, and their collecting work tells us how Anglo American society viscerally understood the history, culture, and mythology of a region that has long maintained a place within many societies' imagination and historical experience.