This is an open access volume and it containscontains several number theory contributions, most of which were written in connection to the workshop WIN6: Women in Numbers, held in March 2023, at the Banff International Research Station (BIRS) in Banff, Alberta, Canada. The chapters comprise research outcomes from collaborations initiated during the workshop as well as other original research contributions. The volume also aims to introduce central research topics in number theory to advanced graduate students and recent PhDs. In this book, more background and details will be given than in standard journal papers.   The workshop and this volume are part of the  Women in Numbers network, aimed at highlighting the research of women in number theory as well as increasing their participation and bolstering collaborations of women mathematicians in number theory and related fields. This is an open access volume and it contains several number theory contributions, most of which were written in connection to the workshop WIN6: Women in Numbers, held in March 2023, at the Banff International Research Station (BIRS) in Banff, Alberta, Canada. The chapters comprise research outcomes from collaborations initiated during the workshop as well as other original research contributions. The volume also aims to introduce central research topics in number theory to advanced graduate students and recent PhDs. In this book, more background and details will be given than in standard journal papers.   The workshop and this volume are part of the  Women in Numbers network, aimed at highlighting the research of women in number theory as well as increasing their participation and bolstering collaborations of women mathematicians in number theory and related fields.