Jazz is a type of music developed by black Americans about 1900 and possessing an identifiable history and describable stylistic evolution. It is rooted in the mingled musical traditions of American blacks. More black musicians saw jazz for the first time a profession. Since its beginnings jazz has branched out into so many styles that no single description fits all of them with total accuracy. Performers of jazz improvise within the conventions of their chosen style. Improvisation gave jazz a personalized, individualized, and distinct feel. Most jazz is based on the principle that an infinite number of melodies can fit the cord progressively of any cord. The twenties were a crucial period in the history of music. Revolutions, whether in arts or matter of state, create a new world only by sacrificing the old. By the late twenties, improvisation had expanded to the extent of improvisation we ordinarily expect from jazz today. It was the roaring twenties that a group of new tonalities entered the mainstream, fixing the sound and the forms of our popular music for the next thirty years. Louie Armstrong closed the book on the dynastic tradition in New Orleans jazz. The first true virtuoso soloist of jazz, Louie Armstrong was a dazzling improviser, technically, emotionally, and intellectually. Armstrong, often called the "father of jazz," always spoke with deference, bordering on awe, of his musical roots, and with especial devotion of his mentor Joe Oliver. He changed the format of jazz by bringing the soloist to the forefront, and in his recording groups, the Hot Five and the Hot seven, demonstrated that jazz improvisation could go far beyond simply ornamenting the melody. Armstrong was one of the first jazz musicians to refine a rhythmic conception that abandoned the stiffness of ragtime, employed swing light-note patterns, and he used a technique called "rhythmic displacement." Rhythmic displacement was sometimes staggering the placement of an entire phrase, as though he were playing behind the beat. He created new melodies based on the chords of the initial tune. He also set standards for all later jazz singers, not only by the way he altered the words and melodies of songs but also by improvising without words like an instrument (scat singing) (Arnold12). Armstrong was a great musical architect. He brought a superb sense of drama to jazz solo conception. During a period when most improvisers were satisfied simply to embellish or paraphrase a tune, Armstrong himself was a master at both. Armstrong^s command of the trumpet was arguable greater than that of any preceding jazz trumpeter who recorded. In actuality, the revolution initiated by Armstrong took place in fits and starts, and with little fanfare at the time. After Armstrong^s departure from the King Oliver Creole Band, over a year would transpire before he would record as a leader. And even when those famous recordings were planned -the classic "Hot Fives"- the record company considered enlisting a better known leader to front the band. Most accounts stress that Armstrong^s talents may have been neglected by the general public, but were amply recognized by the musical community - " his playing was revered by countless jazz musicians," runs a typical commentary - but even this claim is suspect. Fletcher Henderson, Armstrong^s first major employer after Oliver, made the trumpeter accept a cut in pay to join his band. Many accounts suggest that Henderson, in fact , preferred the playing of cornetist Joe Smith, And that Armstrong was hired only because Smith was unavailable. Smith lacked Armstrong^s rhythmic drive, yet his warm sound and ease of execution could hardly be faulted and may have been better receive by the average dancehall patron. Henderson was not even enthusiastic about Armstrong^s singing, an attitude that deeply frustrated the new band member. Years later Armstrong would later exclaim: " Fletcher didn^t dig me like Joe Oliver. He had a million dollar talent in his band and he never thought to let me sing." During the 1930s a new style of jazz emerged. It became the most popular kind of jazz in the twentieth century. This style began during the late 1920s and continued to the 1940s. Most jazz from the 1930s and early 1940s is called "swing music," and this time in history is now known as "the swing era." Big bands in the swing era were made up of ten or more musicians whose instruments were grouped into three categories called "sections:" rhythm, brass, and drums. The brass section included trumpets and trombones. The saxophone section was separated from the brass section because they originated from instruments made of wood. In a big band the sax section contained from three to five musicians. The size of the trumpet section varied from two to five musicians, two or three being the standard. Unlike the early jazz era, in the swing era hits that were jazz-oriented contained only a few solo improvisations, often only one. Swing music contained less collective improvisation and more solo improvisation, and the amount of improvisation in most swing era hits was small. The construction of improvised solos in most hits were melodically conservative. The onset of the Great Depression had a chilling effect on the jazz world, as it did the whole entertainment industry. The ambiance of jazz culture were demystified in the process. During this period, the growing popularity of talking movies led many theaters to halt the elaborate live shows that had previously been a staple of popular entertainment in most cities, further reducing paying jobs for musicians. Although the development of the 1930s affected most musicians adversely, a handful of performers benefited considerably from the more stratified structure of the entertainment world. The creation of a truly nationwide mass medium in the form of radio catapulted a few jazz players to a level of celebrity that would have been unheard of only a few years before. Benny Goodman sent this apparatus into motion with a vengeance. In the process, he ignited not only his own amazing career, but sent off a craze for "swing music" that would last over a decade. As a soloist Goodman defined the essence of the jazz clarinet as no other performer, before or since; as a bandleader, he established standards of technical perfection that were the envy of his peers, while his influence in gaining widespread popularity for swing music was unsurpassed. A decade later he reformed his ensemble to tackle the nascent sounds of bop music (Gioia 135). The new styles , which emerged after 1940 were classified as modern jazz. Bebop is classified as modern jazz. Modern jazz did not burst upon the jazz scene suddenly. It developed gradually through the work of swing era musicians. Rather than being a reaction against swing styles, modern jazz developed smoothly from swing styles. Bop differed from swing in a number of performance aspects and stylistic aspects. Melodies and harmonies were more complex in bop. Bop tunes and cord progressions projected a more unresolved quality. Drummers played their time keeping rhythms primarily on suspected cymbal, rather than snare drum, high-hat, or bass drum. Chick Corea grew and matured as an artist. He joined the ranks of Herbie Hancock, Bill Evans, and McCoy Tyner as the Most prominent and most imitated pianist in jazz. His style originated with aspects from the approaches of bud Powell, Horace Silver, Bill Evans and McCoy Tyner and the classical pieces of twentieth-century composers Paul Hindemith and Bela Bartok. Latin-American music also inspired Corea^s style. Early in his career, Corea had played in several bands that featured Latin-American music. Corea^s crisp, percussive touch enhances the Latin feeling. It is also consistent with his bright, very spirited style of comping. Like Tyner, Corea voiced chords in fourths. Voicing in fourths means that chords are made up of notes four steps away from each other. Chick Corea joined Miles Davis^ band in 1968, and played electric piano on the landmark In a silent way, album and the influential "Bitches Brew" session. His own trio recording with Miroslav Vitous and Roy Haynes, "Now He sings, Now He sobs," became a staple in the record collection of modern jazz lovers during the late sixties. Corea was a prominent composer during the 1960s and 1970s. Corea wrote pieces that made good use of preset bass lines in accompaniment, particularly those with a Latin-American flavor. In 1985, Chick Corea formed the Elektric Band, which became known for its use of synthesizers. The band^s debut was with Chick Corea Eleckric Band, on GRP Records.