A casino is a gambling establishment that offers a variety of games to patrons. Casinos are designed to provide a high level of entertainment for their customers and to maximize profits. They do this by establishing a mathematical expectancy on every bet placed and by offering special inducements to big bettors. These inducements often include free spectacular entertainment, elegant living quarters, reduced-fare transportation and hotel rooms, as well as complimentary drinks and cigarettes while gambling.

While gambling probably predates recorded history, with primitive protodice and carved six-sided dice found at many ancient archaeological sites, the modern casino evolved in the 16th century during a craze for gambling. In Italy, aristocrats gathered in private gambling houses known as ridotti to enjoy their passion. Because they were technically not public, these clubs were largely unfettered by legal authorities.

In the United States, casinos started appearing in the 1970s, first in Atlantic City, New Jersey, and then on American Indian reservations, where they are not subject to state antigambling laws. From the 1980s on, casinos also began opening in various American cities and towns.

Casinos have become increasingly technologically sophisticated, using video cameras to oversee table and slot machines, as well as microcircuitry in betting chips to track the exact amounts wagered minute by minute and warn of any statistical deviation from expected results. They also use software to detect suspicious behavior, such as a player raising their bets or placing chips in multiple spots at once.