All characters, most creatures, and some objects use a set of four attributes to describe their basic capabilities: Strength, Agility, Intellect, and Will. Each attribute has a score, a number from 1 to 20, that measures how adept the creature or object is at performing activities related to its use. A typical person has a score of 10 in each attribute. A higher score indicates exceptional ability, while a lower score describes a diminished capacity.

The score also determines the attribute modifier, which is always equal to the score minus 10. If you have a Strength score of 12, you have a +2 Strength modifier. If you have an Agility score of 9, you have a –1 Agility modifier.

Strength represents muscle power, durability, athletic ability, and overall fitness. You use Strength to resist effects that force you to move or that restrain you, as well as when you climb, swim, attack with most hand-to-hand weapons, kick down a door, or overpower another creature. Strength also helps you withstand or fight off the effects of pain, injury, poison, or infection.

Agility encompasses poise, dexterity, balance, and reflexes. You use Agility when you want to keep your footing, perhaps because someone has just shoved you or you are moving across challenging terrain. Agility also comes into play when you attempt a task that requires manual dexterity, such as picking a lock, disarming a trap, or performing a feat of legerdemain.

Intellect measures intelligence, wit, memory, and knowledge. You rely on Intellect to thwart an effort to deceive you, decipher a coded message, or outwit another creature. Intellect also governs your ability to use some forms of magic.

Will describes courage, willpower, resolve, and mental fortitude. You use Will to resist efforts to erode your confidence, manipulate your emotions, or terrify you. As with Intellect, Will is also needed to use some forms of magic.