“With this Perk you gain +1 to your (Statistic).”— Fallout 2 in-game description
Gain is a perk in Fallout 2, Fallout Tactics, J.E. Sawyer's Fallout RPG and Van Buren. In later games, it was replaced by Intense Training.
This is a series of perks (Gain Strength, Gain Perception, etc.) which will modify the selected primary statistic by +1. Each statistic can only be boosted once, and only to your racial maximum.