The precise origin of gambling is unknown. Probably some form of it has existed in every society throughout history. But the casino as a place where gamblers could find a variety of ways to play under one roof did not emerge until the 16th century, when a gambling craze swept Europe and Italian aristocrats used private rooms known as ridotti to entertain guests.

Today casinos are more sophisticated, with video cameras and electronic systems that oversee the games themselves. For example, chips with built-in microcircuitry interact with electronic systems in table games to enable casinos to monitor exactly how much each player bets minute by minute and to alert them to any anomaly; and roulette wheels are electronically monitored to discover quickly any statistical deviation from their expected results.

Gambling is a social activity that takes place in public, either in games of chance or in poker and other card games that involve some element of skill. Players interact with other gamblers, shout encouragement, and waiters circulate to serve alcoholic drinks. The entire casino environment is designed around noise, light and excitement.

Casinos make a profit by charging fees and taking commissions, called rakes, on wagers. They also give out complimentary items to attract and keep gamblers, known as comps. In addition, they use the profits from their slot machines and other games to pay for luxuries such as free shows, food, transportation and hotel rooms. But critics charge that the social costs of problem gambling, including treatment for addicted gamblers and lost productivity from workers in casinos’ service industries, offset any economic benefits a casino might bring to a community.