A casino is a gambling establishment, usually with an exotic location, that houses a variety of games of chance and is operated by professional staff. These games may include poker, blackjack, roulette, baccarat, craps, and slot machines. Many casinos also offer a variety of restaurants and free drinks. Casinos may be part of large resorts or be stand-alone buildings. In addition to providing a venue for gambling, some casinos host entertainment events such as concerts and stage shows.

Something about the presence of large amounts of money seems to encourage both patrons and employees to cheat or steal, either in collusion or independently. This is why casinos spend so much time and effort on security. Cameras are the most basic form of security, but they can be supplemented by rules of conduct and behavior, and by a variety of other technologies.

In modern casinos, elaborate surveillance systems provide an eye-in-the-sky view of every table, window and doorway, and can be adjusted to focus on suspicious patrons by security workers in a separate room filled with banks of monitors. Electronic systems allow casinos to supervise the exact amount of money being wagered minute by minute, and detect any statistical deviation from expected results.

Beneath the varnish of flashing lights and free drinks, casinos are built on a bedrock of mathematics, designed to slowly bleed patrons of their hard-earned cash. For years, mathematically inclined minds have tried to turn the tables, using their knowledge of probability and game theory to exploit weaknesses in a rigged system. Many of these attempts have failed, but a few successes have spawned an industry of books and websites offering strategies that can give the gambler an edge.