Blue Note Records has been many things over the course of its 75 years: a label responsible for blinding jazz innovations, a home for the titans of hard bop and soul jazz, a place for smart, sly, jazz-inflected pop creations. One constant running throughout its history is improvisation. Its records have showcased jazz soloing in every possible mood and temperament. Its artists, both the jazz legends and those journeymen who are little regarded today, have helped shape the ever-evolving notion of what a solo is and what it can be. To honor the label, we've combed the vaults to select...