I'm not sure I follow. The wiki is rather comprehensive
http://witcher.gamepedia.com/Witcher_Wiki
Right in the middle of the screen, under
Content you select the game (The Witcher, The Witcher 2, The Witcher 3)
Also, if you look on your left you will find different menus where you can select the game and in the submenus you can select what to view - characters, monsters, quests, etc.
There is also a search option