Scribus is open-source Desktop Publishing software (it works on Windows, MacOS, Windows, and other operating systems). It’s been around since 2001, and is probably the most robust piece of open-source Desktop Publishing software available.
“Why on earth should I use Scribus? Because it’s reliable and Free. Free really means Free with an uppercase F. Free is more than just gratis (which is just a side-effect). It means that you are in control of your data and, if you wish, the code of your desktop publishing tool. That’s what smart individuals and companies prefer.”