Her win was reminiscent, in some respects, of Herbie Hancock’s unexpected triumph at the 2008 Grammys, when “River: The Joni Letters” (Verve) won album of the year. Then as now there was startled disbelief outside the precincts of jazz, and giddy jubilation within. And, then as now, there was reflexive talk of real music prevailing, righteously. But Mr. Hancock is Mr. Hancock: not just a brilliant pianist but a grand elder and crossover pioneer, just the sort of guy to earn the loyalty of voters in the Recording Academy. (On Sunday his self-released 2010 album, “The Imagine Project,” earned him two awards, for best improvised jazz solo and best pop collaboration with vocals.)

Ms. Spalding is something else: a charismatic whirlwind proudly hailed, for a while now, as some kind of vital infusion for jazz. Certainly she arrived with great reserves of talent and composure, becoming, at 20, one of the youngest musicians hired to teach at the Berklee College of Music, where she had just earned her degree. She released an auspicious instrumental debut, “Junjo” on the Ayva label in 2006, and an unfocused but appealing vocal follow-up, “Esperanza,” on Heads Up International in 2008. The album she released last year, also on Heads Up, is “Chamber Music Society,” which presents her lissome, light-gauge voice in a sparer light, framed by quietly sparkling arrangements. It’s a good album, though it probably didn’t deserve a Grammy nomination, and didn’t get one. Which raises another question: Not who, but why Ms. Spalding, and why now?