Roulette is a casino game in which players place bets on a single number, various groupings of numbers, the colors red and black, or whether a number is odd or even. A spinning wheel determines the outcome of the bets. The game originated in France in the 18th century, and it is derived from the older games hoca and portique. The earliest written account of the game dates from 1716 in Bordeaux.

A roulette wheel consists of a solid wooden disk slightly convex in shape, with metal separators around its rim called frets and compartments or pockets between them. Thirty-six of the compartments on a European-style wheel are painted alternately red and black, while the remaining two (on American wheels) carry the signs 0 and 00. The wheel is balanced on a metal shaft in a perfectly machined housing.

Before each spin, the dealer gives players time to place their chips on the table. Bets are divided into two major groups: Inside and Outside bets. Inside bets cover individual numbers within the main grid (1 to 36) and offer higher payouts, but lower odds of winning. Outside bets cover a larger area of the table and include the zero and 00, as well as the first (12-13, Premiere douzaine or P12), second (16-23, Moyenne douzaine or M12), and third (25-36, Derniere douzaine or D12) dozen groups. Outside bets have lower payouts but better odds of winning.

There are thousands, maybe millions, of betting systems for playing (and supposedly winning) roulette. Most of them have been disproved by mathematicians, and the fact is that the house edge in roulette is very large.