While Tradeskills determine a character’s general crafting aptitude, Knowledges determine which items that character actually has the ability to craft immediately. Think of them as the crafter’s recipe book, a collection of items the character can create when given the proper components. Players with the Axe 1 Knowledge have recipes for a selection of axes, each with different stats. Meanwhile, a Clothing Knowledge, like T-Shirt, gives the player a colorful variety of shirts from which to choose.
Characters acquire Knowledges in four primary ways. They can visit trainers, who have a supply of books that teach Knowledges. They can find Knowledges in treasure books dropped by some creatures. And some special Knowledges are given as mission rewards. Characters can also conduct research to advance their ability in a Knowledge that they already have. For example, if a character has the Stewing 1 Cooking Knowledge, Stewing 2 is one of the recipes. Completing that recipe gives access to a new collection of palate-pleasing stews and soups.
Knowledges also have a built-in tier system of Improved and Advanced recipes that raise the quality of items their recipes produce. If a player has Improved Stewing 1, he or she can craft items useable by low-level characters but with stats comparable to a higher-level item. Advanced Stewing 1 gives a similar, but more pronounced, boost.