From Ultima Codex
Ultima Online describes a skill which allows the player to either find hidden traps or players that have hidden away from sight with the skill Hiding. It should not be confused with Tracking, which just shows the rough location of the invisible being. It is used by searching a selected area. The better the skill, the bigger the area searched and the more thorough the search is. Characters using the skill Stealth are detected automatically, if getting into 4 tiles of the player. The skill always works 100% in the player's home.
This skill has no reccomended training methods, it can only be trained by "learning by doing", i.e. using it often and actively.