The Encyclopedia system in Forsaken World is a compendium of information that is useful to look through if you have any specific questions you want to look up answers for. You can find information on anything from skills to quests, and everything in between.
To unlock this feature, you will need to reach Freedom Harbor with your character, and complete the Macropedia quest. Once completed, this feature will pop up automatically to let you know that it is now accessible.
To access the Encyclopedia, open the system menu by clicking the gear icon in the upper right hand corner, and then selecting the "Encyclopedia" option at the top of the list.