Item Seach is arguably the most useful window that we have made. It shows you all possible ways of getting any item in the game. You can open this window by clicking Item Search in Main Menu.
First of all, find item that you are interested in. You can search for it by the name, select one of the items from your inventory or select it from the list of Favourites(you can add items to it by clicking on Star in next window).
When you find item you are interested in, click on its name to see detailed information. First tab of Item Search are Monsters, it shows all monsters that can give you this item by Drop or Spoil.
After clicking on the Icon, you can see all drops, spoil and spawn places of selected monster.
Next tab shows all Npcs that trade or sell the item. You can also open the map to see where npc is exactly(except for npcs that move around, like Mammon).
Sell Store tab, shows all players who have Sell Store with this item. You can click on the icon to find out where he is exactly.
Buy Store is similar. Instead of stores that sell item, it shows all the stores that wants to buy it.
Next Tab shows all recipes that allow you to craft the item.
Clicking on Recipe Icon, opens Recipe Information(all items that you need for crafting) and all dwarfs who currently can craft this item for you.
Quest tab shows all quests that have desired item as their reward.
Tab Other, shows any other way of getting the item. It shows items you get by crystallization, becoming Castle Lord or Hero, opening Capsules etc.