As the title of this thesis suggests, presenting one’s self in modern-day society can sometimes resemble a trial-and-error process. In this bachelor’s thesis, the aim is to examine nine Swedish public libraries’ self-presentation through their social media expressions, thus to provide a contemporary overview of what content is being published in relation to the public library organization’s identity formation within the social media platform Instagram. In order to achieve this, following research questions are asked: What kind of content do libraries convey via their Instagram accounts, and what different types of library-specific genres emerge from the empirical material?; Which diverse representations of the public library, library activities and the librarian are conveyed in the empirical material, and how do they relate to more general understandings of the librarian and the library?; How can the selves that emerge in the library's self-presentation on Instagram be seen as an expression of an institutional, professional or media-specific identity, and what impact does technology and the library's social media genres have on how these are shaped?  Using a categorization scheme, consisting of six content categories, this is conducted through a content analysis of 607 library-generated Instagram posts. Based on the empirical evidence the result indicates that four themes in particular emerge as especially present and recurring in public libraries’ Instagram publications. These themes can be summarized as Tributes, hashtags and societal trends; The public library, building and place; The librarian; and The book. Through the libraries’ social media channel, their Instagram posts and mentioned themes, library-specific genres related to the library’s and librarian’s self-presentation seem to occur, which appears to go beyond professional and institutional identities. Therefore, it seems possible to talk about a specific social media identity, ergo Instagram as a new arena for the public library’s mediated self-presentation.