What are the rules of the card game War and how do players determine the winner in a tie situation?

In the card game War, players each draw a card from their deck at the same time. The player with the higher card wins the round and takes both cards. In a tie situation, players go to "war" by placing three cards face down and then drawing a fourth card. The player with the higher fourth card wins all the cards in the war. The game continues until one player has all the cards or a predetermined number of rounds is reached.