For Miles Dewey Davis there was no going back. Such is the task of the historian or the nostalgic, not for those pushing the frontiers of creation in the here and now. Miles, as no other modern American musician, defined a music that transcends narrow categories of what is and what is not "jazz." Miles asserted a living ownership over his music, his times, and his America, integrating his understanding of all three into a creative melange that baffled many of his contemporaries and critics, yet fully endures today. The magnitude of Miles's music continues to reverberate through time, as music itself rises to appropriate (through sampling) and extrapolate (through hip-hop, techno, etc.) on ideas he laid down. From the 1940s to the 1980s, his innovations defined important shifts in jazz, repeatedly altering dominant conceptions of tradition, expanding the possibilities.

Miles Davis was not ahistorical and antitraditional. He did not pursue innovation and new sounds out of some iconoclastic or futuristic predisposition. He created firmly within the historical context of his music and his times, while at the same time helping to redefine both. Miles as innovator was the quintessential modernist, as innovation can be understood as the central feature of modernism. Upheaval and conflict have clearly come to define both modernism and the impact of the music of Miles. Beginning in the 1940s, with his participation in the bebop movement, Miles remained in the vanguard of evolutionary and revolutionary points in the history of jazz.

Challenging the contemporary expectation of jazz as mere dance music, Miles confronted audiences with artistic forms of expression that demanded real listening, not escapist frivolity. Miles, by refusing to clown, grin, and swing, insisted that the musician be heard on artistic terms, not measured by the tired entertainment standards of the era. In the post-Depression 1940s, with the economy reasserting itself in force, young African-American innovators such as Miles, Bird, Dizzy, and Monk helped reassert the artistic importance of the musician. At the same time, they altered the existing tastes of the audience, building receptivity toward a "modern jazz" experience, distinct from the popular entertainment of the dance hall.

Miles and the giants of bebop differentiated themselves from the mainstream world of popular entertainment, defining a "hip" subculture and a subversive musical art form. Miles, influenced by the sharp dressed Dexter Gordon & Billy Eckstine, was a "clean motherfucker" whose style and breathtaking playing influenced the listening public's perception of him and the music. Musicians, fans, critics, and white beatniks embraced both the art and (what they interpreted as) the lifestyle of this new form. But berets and bongos were not the essence of this new esoteric subculture. Its substance was based on a new self-conscious and artistically innovative strain of music and ideas. The innovators of bebop introduced far more than a stylistic pose into American culture, as their music pushed jazz away from the older styles and attitudes more intertwined with popular musical genres and narrow conventions of entertainment. While never supplanting popular music, the 1940s witnessed the ascendance of this group of highly inventive musicians, who demanded and were in time accorded the respect appropriate for leading a significant movement of American artists.

Miles continued to grow musically while many of his bop contemporaries became singularly committed to the tenets of their music, as rigid as the conventions of the swing musicians and entertainers they had rejected. Birth of the Cool represented Miles's self-conscious departure from the stagnation and excesses of bebop. Slowing the tempos down from breakneck paces, he subordinated virtuoso displays of technical prowess to a more subtle layering and orchestration of sounds. The cult of the individual star soloist gave way to the integrated role of the player, who contributed his voice in a complex blending and juxtaposition with the voices of other instruments. Innovative and fresh, Miles even used a tuba for the first time as a melodic jazz instrument. Unlike bebop, which had been characterized, at least in its initial stages, as exclusive of whites, Miles used white players, all of high caliber, on the recording. Particularly after meeting Gil Evans, Miles "understood that all white people weren't the same," but more importantly, Miles was "hiring a motherfucker to play, not for what color he is."

Miles not only established his new sound, but moved jazz out of its more alienating context of bop dissonances and jagged phrases, reclaiming the humanity of the melody. Here was a music where you could not only hear everything, like the music of Duke Ellington, but "you could easily hum [it] on the street with your girlfriend trying to get over with a kiss." The listening audience came to embrace the cool of Miles, even as Bird and bop lived, pushing jazz in a new direction. Additionally, he helped establish the careers and shape the sound of his side-men, who built the West Coast jazz movement around his "cool" aesthetic. Miles noted the tragic irony of his times, as it was the "white people who were copying my Birth of the Cool things [who] were getting the jobs, " while he himself was getting few gigs. Perhaps, as Miles cynically observed, much of the listening audience "always liked to see white people up in black shit, so they can say they had something to do with it."

By 1968, Miles, who had been driven through all his musical stages by the need to create new forms for expression, was going through exciting musical changes, listening and playing "things [which] were leading me into the future and into In a Silent Way." Miles's music and lifestyle were being influenced by the wave of new sounds and ideas that characterized the efflorescence of late Sixties. He felt the new "music that was happening everywhere was incredible," and responded deeply to the music of James Brown, Sly and the Family Stone, and Jimi Hendrix. While young people were packing stadiums to hear this new music, "jazz music seemed to be withering on the vine." Miles's mid-Sixties quintet had pushed acoustic jazz to the limits, especially in light of both the advances of his co-improvisers (Shorter, Hancock, Williams, Carter) and the apparent and general exhaustion of the old theme and variations approaches. Miles metamorphosed the new sounds reverberating between his ears. He threw away Zawinul's cord sheets, transformed the melody into a sublime electric mantra, and "brought in music that nobody had ever heard." In a Silent Way "came out beautiful and fresh." While the bebop revolution took place within the jazz tradition, 1969 witnessed Miles's most fundamental self-declarations of independence from jazz tradition: In a Silent Way and Bitches Brew.