This is where fans of the group can sort of stop and settle down at last.

MCA Records had previously let the Mamas & the Papas' music out on CD in a trickle; the debut LP was upgraded and a compilation of remastered hits showed later in the decade, but the rest was left to languish.

This two-CD set makes up for that neglect, assembling all four of the quartet's '60s albums on two CDs and augmenting them with the mono single versions of "I Saw Her Again," "Words of Love," and "Creeque Alley," plus the non-LP single "Glad to Be Unhappy." One just wants to luxuriate in the sound of this reissue and its little details, like the rhythm guitar on "Do You Want to Dance" that cuts right through the air, the string basses on "Go Where You Want to Go" that sound like they're just across the room, and the rest of the first album.

The real keys to the value of this set, however, are the second and third LPs by the group, superb albums which were either never reissued on CD at all or never upgraded from the mid- to late '80s.

The group's second album has never enjoyed as strong a reputation as its predecessor, possibly because of the painful and convoluted circumstances under which it was recorded (Michelle Phillips was fired and then reinstated a few weeks later, but a version of the cover does exist that features Phillips' temporary replacement, Jill Gibson, in the lineup).

The songs may not quite match up to the selection or the sense of free experimentation that went into the first album, but coming from any other group, the contents of The Mamas & The Papas LP would have been considered a triumph.

"No Salt on Her Tail" and "Trip, Stumble & Fall" could have been outtakes from the first album, while "Dancing Bear" put them into Peter, Paul & Mary territory.

"Words of Love" didn't quite come up to the standard they'd set for themselves, but "My Heart Stood Still" nearly succeeds in turning the Rodgers & Hart standard into a folk-rock piece of incomparable beauty.

The whole second half of the disc is a revelation in sound, simply because apart from the hits, none of its material had shown up on CD before, and here it is with resolution so close that Joe Osborne's bass sounds like it's practically in the listener's lap.

Cuts such as "I Can't Wait" and "Strange Young Girls" -- although the latter is never cited as a strong point, it has a depth and richness in its appearance here that calls to mind textural echoes of the Beach Boys' Pet Sounds album -- and "Once Was a Time I Thought" (where they tread onto Spanky & Our Gang-cum-Manhattan Transfer territory) help make this set essential to virtually any fan of the group.

The quartet's third album, Deliver, which is divided between the two CDs, is similarly improved in a startling upgrade from the mid-'80s CD that makes their version of "My Girl," in particular, sound gloriously radiant.

Their fourth album, Papas & Mamas, although never in the same league with the group's earlier records, can be considered nearly essential musically for the upgrade on "Rooms," "Too Late," "Mansions," and the classic "Twelve Thirty (Young Girls Are Coming to the Canyon)." As an added attraction, in addition to the single mixes on three of their hits, the disc also features superb notes built around recollections by the surviving members of the group and longtime session musicians, such as Eric Hord.