The aim of this Master’s Thesis is to contribute knowledge regarding the reasoning of public librarians with a focus on young adults (YA) when it comes to the design of the library’s YA space and its activities. The research questions focus on the staff’s basis for the design of the YA space and its activities, and what role the relation to the users plays in the design. To collect the data, nine YA librarians from eight public libraries across Sweden were interviewed using a semi-structured interview technique. The data was subsequently transcribed and analysed using Thematic Analysis from the theoretical perspective of the four-space model by Jochumsen et al. (2012). The analysis showed that the YA space provides the users with areas for reading, playing board games and studying and houses events and recurring activities, often with a creative spin. Some activities clash with those of other users. The staff provides support to user-led activities like book clubs, and they also assist the users in other projects. The staff believe that the YA deserve a space of their own in the library and that space should ideally be designed to support different activities simultaneously and interchangeably. The staff form relations with the YA as part of their job and they want them to feel welcome and involved. The staff also strive to inspire and support their undertakings.