Mr. Eubanks had come to the show with an artistic identity

Mr. Eubanks had come to the show with an artistic identity Mr. Eubanks, 52, has said that it was a desire to refocus on music, rather than any problem with Mr. Leno or NBC, that motivated his decision to leave the show. “I want to play some music, and not just jazz,” he told The Philadelphia Inquirer recently. “Other genres too. It’s weird but I don’t consider myself just a jazz musician.” (Mr. Eubanks did not respond to interview requests for this article.)

His resistance to pigeonholing is true to form, and to his own history. Growing up in Philadelphia, Mr. Eubanks played extensively in Top 40 and funk bands, even as he built a jazz career. A virtuoso who had synthesized jazz-rock, funk and the blues, he was well suited to the task of a late-night bandleader. “I’m just trying to take advantage of the fact that I’m able to access a lot of different types of music genuinely,” he told me in 1999.

But his Tonight Show Band was always admirable for its versatility, Montreal canadiens vitality and polish, more than any distinctiveness of style. Partly that’s a reflection of the job. It speaks volumes that Mr. Eubanks’s successor won’t be a solo artist of any stripe but rather Rickey Minor, who until last week was the musical director of “American Idol.”

By contrast, Mr. Eubanks had come to the show with an artistic identity, which has since been muddled, and not just by his network responsibilities. Over the last decade Mr. Eubanks has released six albums, largely unnoticed, on his own boutique label, InSoul. Their mood is drowsy, skirting New Age sensibilities, though the musicianship never wavers. “Soweto Sun,” from 2006, has some exquisite acoustic guitar playing. But the gentility can be lulling.

So let’s say you started further back, with “Live at Bradley’s,” a study in expressive, idiomatic hard-bop, made with the pianist James Williams and the bassist Robert Hurst. What it tells you about Mr. Eubanks is that he can handle a mainstream jazz-guitar dialect, the one defined by Wes Montgomery, as cogently and compellingly as anyone.

What doesn’t it tell you? For one thing, much of what Mr. Eubanks was up to in the early 1980s, when he was one of the more important new arrivals on his instrument. “Guitarist,” his 1982 debut, originally issued on Elektra/Musician and now on the Wounded Bird label, lays out a strong introduction, showcasing his breadth of taste and his commanding proficiency in both an electric and an acoustic vein.