From the publisher's website:

Go is an adversarial game with the objective of having surrounded a larger total area of the board with one's stones than the opponent. As the game progresses, the players place stones which map out formations and potential territories. Areas are contested in battles between opposing stones, which are often complex and may result in the expansion, reduction, or wholesale capture and loss of the contested area. The general strategy of Go is to expand one's territory where possible, attack the opponent's weak groups (groups that can possibly be killed), and always stay mindful of the "life status" of one's own groups. The game ends when both players pass, and players pass when there are no more profitable moves to be made. The game is then scored: The player with the greater number of controlled (surrounded) points, factoring in the number of captured stones and komi, wins the game. Games may also be won by resignation, for example if a player has lost a large group of stones.