Baseball bats are commonly made of wood because it is a strong and durable material that can withstand the impact of hitting a baseball. Wood bats are preferred by many players and leagues because they provide a traditional feel and sound when making contact with the ball. Additionally, wood bats allow players to have better control and accuracy while swinging compared to bats made of other materials like porcelain, marble, or lead, which are not commonly used in baseball bats due to their weight, fragility, and safety concerns.