Trumpeters Louis Armstrong and Miles Davis became two of the most influential American jazz musicians of all time by taking very different approaches to their art, but they had more in common than meets the eye, or ear. Armstrong reigned as the most famous jazz musician in the world, Terry Teachout reminds us in Pops, but Davis made the single most enduringly popular jazz album with Kind of Blue, which Richard Williams scrutinizes in The Blue Moment. Teachout, chief culture critic for Commentary, argues that Armstrong is underestimated as an artist, while Williams, a former Melody Maker editor, believes the full impact of Kind of Blue has yet to be fully appreciated. Considered together, both books reveal how much the pair shared beyond incomplete recognition of their accomplishments, despite the younger man’s deliberate efforts to distance himself from a predecessor he couldn’t help but grudgingly admire.

Armstrong liked to believe he was born on July 4, 1900 (he probably actually arrived a year and a month later), and he liked to say that he and jazz were born together. While he was not among the first jazz players, “he was the first great influence in jazz”, according to Teachout, who calls recordings Armstrong made in the mid-1920s “the first chapters in what was to become the Old Testament of classic jazz.” These rhythmic scriptures attracted many disciples in the United States and Europe. Indeed, Armstrong achieved widespread recognition in England before doing so stateside. His trips to Europe helped spread the musical gospel: “He . . . left his mark on a generation of European musicians who drank deeply from the well of his genius.”

Teachout thinks his “gritty tenor voice” is the key to Armstrong’s impact: Thanks to the then new technology of commercially available sound recording, “Armstrong was the first jazz musician whose voice was heard by large numbers of people.” Consequently, he was able to impress “his personality on all who heard him, even those who found most instrumental jazz to be unapproachably abstract.” With a voice “as recognizable as fingerprints”, he made songs into standards that continued to be performed decades after he recorded them. Teachout believes Armstrong’s singing “gave these records their commercial appeal.” His use of “improvised nonsense syllables”, what came to be called scat, in place of song lyrics inspired many imitators. Billie Holiday and Ethel Waters both attested to his influence on their singing. “Armstrong didn’t invent...