Lottery is a type of gambling in which numbers are drawn for the prize. The casting of lots for decision making and the determination of fates has a long record in human history (see, for instance, a numbering system in the Bible). In modern times it became quite common for the public to organize a lottery and thereby raise money for the poor or for many other uses, especially in Europe and America. Lottery organizers usually require bettors to write their names and amounts staked on a ticket which is then shrunk or recorded for a drawing of winners. The prize amounts are determined by the number of tickets sold, the probability that any particular ticket will be chosen and how much money is needed for a given purpose.

State governments often promote the lottery as a means of raising funds without adding taxes. This argument is very effective in times of economic stress, because the public perceives the lottery as a way to avoid tax increases or cuts in essential services. However, it has also been shown that the popularity of a lottery is independent of its actual fiscal condition, and that the objective financial health of a state does not influence whether or when it adopts a lottery.

Once a lottery is established, it is difficult to reverse its course because of the entrenched interests and powerful lobbying of various groups, including convenience store operators; lottery suppliers, who give large contributions to state political campaigns; teachers (in states where a percentage of the proceeds go to education); and state legislators who quickly come to depend on the steady income generated by the lottery. These interests and lobbying pressures make it very hard to reduce the size of a jackpot or the odds against winning, which can lead to a decrease in ticket sales.