The music contained in “Classic Black & White Jazz Sessions,” the highly recommended new boxed set from Mosaic Records, might be described as a jazz tale of two cities. Black & White Records, which was heavily active (if not always prosperous) in the late 1940s, recorded heavily both in New York and then Los Angeles — yet it was more specific than that. As I wrote earlier, its Manhattan dates were largely reflective of Greenwich Village, and its West Coast activities were tightly focused around Central Avenue.

Although jazz and especially the blues were first heard in the deep South and then flowered, among other spots, in Kansas City and the Midwest, this set offers plenty of evidence that Central Avenue played home to the first flowering of the music about to be christened “rhythm-and-blues.”  

The set features one of the biggest hits of the era — and probably the most significant released by the label — “Open the Door, Richard,” a 1946 single that began as a routine by comedian Dusty Fletcher transformed into a novelty song by tenor saxophonist and bandleader Jack McVea. This tale of a drunken lowlife trying to sneak into his own apartment became so ubiquitous it ended up more than a hit record: It was a cultural catchphrase, the Truman-era equivalent of a viral meme, even to the point where it was referenced in Bugs Bunny cartoons.

The set features almost a dozen major female vocalists, several of whom are captured at the start of what would be long and important careers, often in which they would be part of the worlds of both jazz and R&B. Here’s Etta Jones at 17 in 1945, already a graduate of Buddy Johnson’s orchestra but way before her long collaboration with Houston Person and her career-defining signature song, “Don’t Go to Strangers.” In a date backed by Ellington clarinetist Barney Bigard, composed and produced by Leonard Feather, Jones sings a trio of comic blues tunes that later became hits for Dinah Washington. She comes closest to sounding like her mature self on the Ellington classic “Solitude.”

Ernestine Anderson is all of 19 here in 1947, and, to be honest, I wouldn’t have recognized her voice, especially on these two R&B numbers: a fast, jumpy blues for dancing, “Good Lovin’ Blues,” and a slow, erotic number designed to encourage other physical activities, “K.C. Lover.”

Helen Humes is documented safely in the middle of a long and successful career — she started as a tween blues shouter, then became a big-band vocalist with Count Basie, and spent her final decade or so as a jazz festival headliner. Yet her most lucrative years may have been the late 1940s, when she landed a succession of always swinging, delightfully suggestive hits on the R&B charts. She’s so good at delivering these rhythmical blues numbers — so subtle, yet so direct — that you can’t help but feel that she was already serving as a role model for the younger girl singers here on the label, and elsewhere.

There are R&B gal singers here whom I’d never heard of, like Estelle Edson, who does her version of “Be-Baba-Le-Ba,” which had been a hit for Humes on another label, and Jo Evans, a saucy, deep-voiced temptress. Linda Keene is a blonde, straight-down-the-middle pop singer performing jazz standards with a tasty small band starring trumpeter Charlie Shavers. This is the first and last time most of us are hearing their voices or even their names, but these are sessions worth saving.  

One surprise is Ella Logan, a year before her big breakthrough on Broadway in “Finian’s Rainbow”; here, in 1946, she sings jazz versions of two vintage showtunes by Vincent Youmans in a date co-starring alto saxophonist Willie Smith and produced by Norman Granz. Logan sounds wondrously coy and playful here. 

The delights of this set are almost too plentiful to be enumerated, including King Cole Trio-style music from The Phil Moore Four and the Red Callender Trio. We get a whole album’s worth of modern big-band music from one talented leader who retired at age 23, Earle Spencer, and another, even more gifted arranger-composed, Gerald Wilson, who kept creating new music until his mid-90s.  

There are tons of tenors here, virtually every saxophonist associated with either ’40s Los Angeles jazz or R&B: Maxwell Davis, Bumps Myers, Budd Johnson, Georgie Auld, Charlie Ventura. Also, a whole bebop concert featuring Howard McGhee and a very young and exuberant Lucky Thompson, sounding generations away from his more introspective playing as an expatriate a decade later.

Yet when it comes to naming my favorite music from the Black & White Records, I do not hesitate. Ivie Anderson, roughly four years after her extremely productive decade with Duke Ellington, made her swan song on the label. She does eight songs — a mini 10-inch album by itself — including a remake of one of her Ducal classics, “I Got It Bad (And That Ain’t Good),” three updates of ’20s numbers, and four more contemporary items. Her uptempo “Empty Bed Blues” is magisterial, worthy of comparison with the classic recording by Bessie Smith.  

“Twice Too Many” is a wonderfully wistful, moving ballad; Anderson sings it in dance tempo yet breaks your heart with it just the same.  There’s no doubt that she would have continued to be a major figure in both jazz and blues had she not died a few years later, at 44. It’s worth having this entire massive set just for the Ivie Anderson titles.  Everything else is just so much gravy, but it’s magnificent gravy at that.