Yeah, the first one is an adventure and the last one is the main rulebook (a translation of the 5800 RM FRP). The Arms Law seems to be a bit tricky though. It hasn't been released so I cant tell you all about it but they put some of the professions and TP's from Character Law into it as well. It sais there'll be 4 new professions like warrior monk, 11 new TP's like Assassin, new skills like unarmed combat and so on..
We will have to wait unti the mid of october to see what they put into it though