If your exposure to men’s issues comes from online resources then you might be surprised to find out that there is actually a pretty strong body of offline literature too. The first two books work well as an overview or introduction to men’s issues (one is more philosophical and the other more personal, so they complement each other well). The other books cover other relevant topics (specific men’s issues, gender roles, feminism, etc.) in more detail.
This is a chapter-by-chapter summary of Discrimination Against Men: Appearance and Causes in the Context of a Modern Welfare State, a 2009 doctoral dissertation by Pasi Malmi (University of Lapland) that provides an impressively detailed and balanced investigation of discrimination against men in Finland (the theory and results actually give almost as much detail on discrimination against women, although men will be the focus here).
Chapters 5 to 8 are the most critical. Chapter 5 explains six biases that cause gender discrimination, chapter 6 delineates the patriarchal and matriarchal subsystems of Finnish society, chapter 7 examines the various discourses that justify discrimination against men, and chapter 8 analyzes a database of gender discrimination complaints made to the Finnish gender equality ombudsman, a third of which were made by men.