Simple deejaying has been around for a long time. In Jamaica vans called "sounds," which  were equipped with a record player, amplifier, and speakers, would travel to different neighborhoods and play records. In Manhattan, discos were playing music and entertaining crowds. However in 1973 Kool Herc changed how DJ's would play records.
none other than Kool Herc In 1973 Kool Herc started spinning when his sister Cindy asked to provide the music at her birthday party, which was being held in the recreation room their project in the Bronx. To prepare he bought a selection of records, and did something that is now a standard to all deejays, he hooked two turntables together. With two turntables, and two copies of the same record, he developed a technique called Break-Beat. What he did was play the break of a song, which is a short section of a song without vocals that is good for dancing, on one turntable then switch to the other turntable and play the break, in order to extend the break. Herc ripped it up and continued his craft at community centers, house parties, and clubs.  Besides having the best records and beats he also had one of the best and loudest sound system dubbed the Herculords.  By 1975, Herc moved into the club Helvalo, and later to the Executive Playhouse. Herc's parties there became a premier gathering place for b-boys. B-boys like Sha Sha, Trixie, Amazing Bobo, and the Nigger Twins (brothers Kevin and Keith) were regulars at Kool Herc's parties. he next man to make an advancement in the deejaying is none other than Grandmaster Flash, who has been deejaying since 1974.
Flash began by entertaining at house parties and performing in city parks and by 1976 had achieved notoriety for his skills. While he had talent, he didn't have a system that could touch Herc's in any way and Flash was determined to find another way to set himself apart from the other DJ's.  His chance came when he noticed that DJ Pete Jones, a DJ who spun at clubs in Manhattan, was able to change from turntable to turntable smoothly. In contrast, Kool Herc original turntable wizard Grandmaster Flash was more hit or miss when he did a break beat and the beat would be broken as he switched turntables. After some pleading DJ Pete let Flash take a turn at the wheels of steel for him one night and Flash discovered his secret, Pete had hooked up a pair of headphones to a toggle switch that allowed the DJ to hear what was on either turntable.  Soon Flash had perfected the technique and used it to create phrases by switching between several records in a row, playing a word or two from each. Around this time he developed his clock method of finding a spot on a record, which is pretending the label on the record is a clock face and branching out to find a spot on the record. In 1977 Flash introduces yet another development, that of back-spinning. Back-spinning is playing a phrase from a record and then spins the record back slightly to repeat the phrase.  You can hear Flash do this at the beginning of  "Grandmaster Flash on the Wheels of Steel" when he repeats the phrase "you say" several times.  Another technique that Grandmaster Flash pioneered was that of Punch-Phasing, which is playing one part of a record in quick volume surges on one turntable while the same record plays on the other turntable.  Not only is Flash a master of the turntables he also was a consummate entertainer.  As such he was one of the first DJ's who incorporated tricks like mixing behind his back into his routine.  Grandmaster Flash tried to"Nice to meet you, I am Grand Wizard Theodore, and for show and tell today I would like to demonstrate the scratch"teach his then partner Mean Gene about about break-beat deejaying but he could never pull it off consistently, instead Gene's brother Grand Wizard Theodore did.  Not only did Grand Wizard Theodore pick up on the new techniques that Flash taught him he would develop one of his own. While practicing his skills one day he realized that moving the record back and forth while it was playing produced an interesting sound. He incorporated this sound into his stage show and it became a hit.  Yes ladies and gentlemen, B-Girls and B-Boys, honeys and homies, it was Grand Theodore Wizard who introduced the scratch.  It was these artists and techniques that changed the turntable from a tool to play records to an instrument.  Since then other techniques, like orbits, flares, and beat-juggling have been developed by other individuals, but they are all based on the principles set forth by all of the pioneering individuals above.  Groups like the Invisibl Skratch Picklz have created entire albums, like The Frigger Shagger Show!, out of nothing but work on the turntables.