The history of slots is very old and dates back to 1887 that is more than a hundred years back, when an American mechanic Charles Fey for the first time devised a slot machine. This was a three reel slot machine with five symbols on each of the reels. These symbols were the spade, heart, diamond, horseshoes and Liberty bell. A combination of three liberty bells was the most beneficial in that it gave the highest pay out, and so the machine was named the Liberty Bell.

Gambling was soon banned in California, the home state of Fey, but still the demand for Liberty Bell from other states increased day by day and it was difficult for Fey to keep up with it.

As is true with all other inventions, the idea of Liberty Bell was taken up and modified by many developers. Sittman and Pitt of New York were slot machine developers and in 1891, they developed a five reeled slot machine for the first time using different poker combinations to give the payout. This machine is at the first step of the development of the slot machines that came later.

In 1963, a fully automated electromechanical machine that could itself payout over 500 coins without the help of an attendant was developed by Bally manufacturers. This machine was called Money-Honey.

Video slots appeared on the casino strip in 1976, and gained popularity so much so that they are one of the most famous slots in Las Vegas. The modifications which led to the development of video slots also made the machines more cheat proof.

Modern advanced technology has enabled slot machine developers to increase the number of pay lines in slot machines, so much so that number of pay lines has increased from 9 to 50. These days, slot machines do not use the idea of pay lines at all; rather more than 243 ways have been developed to increase the number of wins.

Slot machines account for most of the games in a casino and take up most of the space besides superseding other games in terms of the revenue they earn. More and more themes, bonus games, coins are being introduced in a lot machines as they move online, leading to increased attraction of the players to the interesting and lucrative game, eliminating the issue of space along.

Software developers are expected to increase the graphic richness of movie based themes in slot machines, and increasing the bonuses for each game.