The concept of the singer-songwriter came to dominate pop music in the 1960s, and therein lies an odd dichotomy. It may have seemed more ambitious for a single artist to write his own songs and sing them, and even accompany himself playing them on guitar or piano, but in actual practice, pop music suffered for the transition. It stands to reason that if one man is going to do a job that is traditionally done by three people, the professionalism of the overall product will probably suffer. Apart from such examples as Bob Dylan and the tandem of Lennon and McCartney, the singer-songwriters of the ’60s, in trying to do more, actually wound up doing much less.

These singer-songwriters were generally inspired not by what had formerly been regarded as mainstream pop, but from the fringes of blues and country music, adjacent fields where it was more common (if hardly the rule) for performers to write their own material. Yet at least three of the greatest songwriters of the 1930s, ’40s, and ’50s were also among the greatest performers of their own music and everyone else’s: Hoagy Carmichael, Harold Arlen, and Johnny Mercer. Sadly, many of their best recordings as singers are hard to find in the CD era, but a recent 3-disc boxed set from Mosaic Records, “Mosaic Select: Johnny Mercer” (www.mosaicrecords.com), is the first comprehensive attempt to collect many of the lyricist’s finest recorded moments.

In 1942, Mercer (1909–76) had been living in Hollywood for about six years, and though he was a few seasons away from winning his first Academy Award (for the original song for 1964’s “Charade”), he was generally regarded as one of the finest lyricists writing for the movies. In the ’30s, Mercer had sung on roughly two dozen recordings, usually sharing space with better-known bands and vocalists, such as Bing Crosby, Benny Goodman, and Judy Garland. In one of the first instances of a creative talent (rather than a businessman) starting his own label, Mercer joined forces with a successful music retailer (Glenn Wallichs) and a well-heeled mogul (Buddy DeSylva) to form Capitol Records, where the idea was that Mercer could produce artists and bands simply because he liked them.

Mercer took a hands-on role in running the label for roughly five years, during which time he nurtured such major talents and mega-sellers as Nat King Cole, Peggy Lee, Stan Kenton, and Margaret Whiting. Almost as a bonus for doing such a great job with the company, he permitted himself the luxury of regularly making his own recordings. Of course, since many of these recordings sold well enough to enter the Billboard charts, they were hardly considered vanity projects. The new Mosaic Select box begins in April 1942, at one of the first sessions for the new label, with a swinging treatment of Jerome Kern’s 1912 “They Didn’t Believe Me.” It then proceeds to a gem of a narrative story-song that was always scarce on both LP and CD: “The Old Music Master,” by Paul Whiteman’s Orchestra, with vocals by Mercer and Jack Teagarden. On the track, a 19th-century classical composer interfaces with a swing-era hep cat. Teagarden’s whisky-soaked low baritone contrasts with Mercer’s squawky, high-pitched, highenergy voice.

Interestingly, though, the majority of these 79 sides don’t satisfy the requirements of the singer-songwriter format because only a dozen of the tunes here are Mercer’s own compositions. What is obvious, though, is that Mercer’s north star, his guiding force, is his determination to tell a story (whether he’s writing it, performing it, or, as on 12 of these songs, doing both). This imperative is most obvious in a subset of recordings in which Mercer doesn’t merely sing, but performs songs entirely in dramatic character. In one case, he takes the voice of a comically lazy Southerner of the type he might have encountered in minstrelsy when he was growing up in Georgia. Mercer plays that role throughout “Sugar Blues,” a devastating parody of old-school Mickey Mouse bands, and “Surprise Party,” a comic turn on which he doesn’t sing so much as wheeze out the notes.

The producers of the Mosaic set, Billy Vera and Scott Wenzel, are also to be commended for including 20 tracks from 1946 originally recorded for radio transcriptions. Like Sinatra’s 1945 album “The Voice,” these tracks amount to a jazz-pop album from well before the invention of the long-playing record. Mercer deliberately avoided his own songs here, preferring instead to put his performing stamp on the jazz-age warhorses of his teens. He salutes many of the great gals of the era in “Sweet Georgia Brown,” “Margie,” “Lulu’s Back in Town,” “Sweet Lorraine,” and “Louisville Lou,” as well as American locales like Indiana, Georgia, and Texas, where it’s round-up time when the bloom is on the sage.

The sides were conducted by Capitol’s house musical director Paul Weston and feature the outstanding, hot tenor sax of Herbie Haymer (who gets off a good solo on “I Never Knew”). The charts were done in a roughly Bob Crosby-esque big-band Dixieland style by the clarinetist Matty Matlock (who solos eloquently on “Sugar”). Mercer is consistently loose and swinging throughout, singing without a trace of self-consciousness or a care in the world. Often he confines himself to 32-bar band vocals, but sometimes he spreads out for the whole track. The most dated, politically offensive track is also the most endearing: Milt Ager and Jack Yellin’s tale of that vampin’ baby, the heart-breakin’, shimmy-shakin’ “Louisville Lou.” Here, Mercer builds to a minstrel show conversation with himself, as if he were a one-man Amos ‘n Andy.

By 1946, Mercer had become such a great duet partner that he could, in effect, sing a duo with himself. In nearly all of his recordings between 1932 and 1940, he’s singing with a famous band or another vocalist. Likewise, many of his most exhilarating performances between 1942 and 1947 are team-ups of one kind or another, including additional tracks with Teagarden, Manone, ace vocal group the Pied Pipers, nascent vocal stylist Jo Stafford, and Ellington trumpet star Cootie Williams. Mercer had worked on a radio series (and one record date) with Benny Goodman in 1939, but their finest moments together came on the 1947 novelty song “It Takes Time” and Kurt Weill’s lovely “Moon-Faced and Starry Eyed.” Mercer is also amazingly simpatico on three hysterical titles with Nat King Cole and his trio from that same year, especially on Danny Barker’s amazingly prescient ode to vegetarianism “Save the Bones for Henry Jones.”

Mercer gave up the active management of Capitol Records after the 1948 recording ban, and, unfortunately, sacrificed his singing career along with it. For this apparent abandonment, Capitol seems to have punished him by refusing to rerelease most of his classic recordings, until now. The only regret regarding the Mosaic Select package is that it only includes three discs’ worth of Mercer’s Capitol tracks: It should be three times that size and include a complete accounting of all of Mercer’s recordings. They just don’t make singer-songwriters like him anymore.

wfriedwald@nysun.com