Pandemic is a cooperative board game designed by Matt Leacock and published by Z-Man Games in 2008. Pandemic is based on the premise that four diseases have broken out in the world, each threatening to wipe out a region. The game accommodates 2 to 4 players, each playing one of five possible specialists:. The game is unlike most boardgames as the gameplay is cooperative, rather than competitive. Through the combined effort of all the players, the goal is to discover all four cures before any of several game-losing conditions are reached. Three expansions, Pandemic: On the Brink, Pandemic: In the Lab, and Pandemic: State of Emergency, co-designed by Matt Leacock and Tom Lehmann, each add several new roles and special events, and rules adjustments to allow a fifth player or to play in teams. In addition, several rules expansions are included, referred to as "challenge kits". Pandemic is considered one of the most successful cooperative games that has reached mainstream market sales, condensing the type of deep strategy that earlier cooperative games, like Arkham Horror, offer into a game that can be played in a limited time by a wider ranges of players.