This Skill Category enables you to sense the presence of magic in an object, creature or area. It also enhances the Diagnose Wounds skill when used on non-spirited creatures. It does not allow you to sense the magical traps known as Glyphs without also knowing the Sense Glyphs skill.
At the first level of Skill, your character can sense the presence of a life force in a creature or a focus object from a distance of two inched in front of their spell casting hand. The second skill level can increase the range at which a life force or focus objects can be sensed to twenty feet directly in front of the characters spell casting hand. Other sense skills can be increased to twenty feet with this level of skill. At the third level of this skill, the range is increased to twenty foot radius, centred on the character, the character can sense the number of Life-Forces and focus objects in the area, but must point his or her spell casting hand directly at one to determine its location, and other sense skills are increased to match the range. At the fourth level of proficiency in this skill, the location of all life forces and focus objects can be determined if within twenty foot of the character, Also, the character can detect any magic within forty feet directly in front of their spell casting hand, again this increases the range of other sense skills. At fifth level of proficiency the character can tell the direction to the Focus North Pole of the world, and the type and strength of focus spell or effect present by revealing the spell list that the effect was cast from, but not necessarily the exact spell. Finally, at fifth level of proficiency, the range of this skill and any other sense skills is increased to twenty feet centred on the character and a circle twenty foot in radius, up to forty feet away. In general you can sense magic though normal objects such as walls, doors, chests, etc. But there are methods to make mundane objects impenetrable to this skill but they are very expensive, and normally only available to Guilds or other people with similar power and wealth.
Please see the attached image to see a diagram of the different levels.