Hello everyone.
I have a weird─probably stupid too─question: what is the difference between Player Companion books and Campaign Setting ones? Are the first intended for players and the latter for GMs? Can I read a Campaign Setting manual when creating a PC, or should I use only Player Companion books?
Thank you in advance for your answers.
Cammpaign Setting and Chronicles add a lot information about the world, but little new character options.
Player Companions may include new information about the world, but they focus on new class options, feats, spells etc.
So, for example, to learn about Dragons of Golarion one should check Pathfinder Chronicles: Dragons Revisited and Pathfinder Chronicles: Dragons Unleashed. To create a character that has ties to dragons, one should rather look into Pathfinder Player Companion: Legacy of Dragons or Pathfinder Player Companion: Dragonslayer's Handbook.
Both players and GMs may use all books. The Campaign Setting and Chronicles books are more useful for understanding the world, while Player Companion books are more useful for creating characters (PCs and NPCs).