Choosing The Best Mahler. Since Bernstein put him in the concert halls, eight full - and varied - cycles of his symphonies have been recorded. RECORDINGS

WHEN Leonard Bernstein ushered in the Age of Mahler during the '60s, with the composer's complete symphonies cycle both in New York Philharmonic concerts and then on CBS Masterworks LPs, he was truly fulfilling Mahler's prophesy, ``My time will come!'' Prior to Berstein's efforts, only Mahler disciples like Bruno Walter and Otto Klemperer, or other conductors like Leopold Stokowski who cherished the challenge of performing such grandiose works as the Eighth (subtitled ``Symphony of a Thousand'') kept the composer's name alive in the world's concert halls.

Now everyone plays and records Mahler. There are eight complete recorded cycles (Bernstein, Abravanel, Solti, Haitink, Kubelik, Inbal, Tennstedt, and Neumann). Two more are well on their way to completion (Abbado and a new Bernstein). One more is nearly complete (Levine). And at least three are just beginning (Ozawa, Sinopoli, and a new Haitink).

As for the older recordings, CBS's Bernstein cycle has been handsomely tranferred to CD. Sir Georg Solti's Chicago Symphony performances of the Sixth, Seventh, and Eighth have been transferred to CD, joining the recent digital recordings of the First, Second, Third, Fourth, and Ninth for a complete CSO cycle. And Philips has nearly completed its transfer of the Bernard Haitink/Concertgebouw set to CD.

So far, DG has moved only Rafael Kubelik's Eighth to CD (DG, analog, 419 433-2, 75 min.), even though that set remains, for me, the most satisfying musically. Even if almost all the others are better recorded, I return most often to Kubelik's honest, lucid, unfussy readings, and he remains the only conductor I have heard who makes the Eighth really work as a whole.

The most commonly recorded of the big works is the Second, and it has received some truly eccentric accounts, including Guiseppe Sinopoli's on DG, which I can't recommend.

More recently, with major fanfare EMI/Angel has released Simon Rattle's inferior account with of the Second with his City of Birmingham Symphony Orchestra (CDS 47962, digital, 2-CD, 86 min.). It is slow, willful, and, most disturbingly, it makes Mahler sound banal.

Fortunately, there is now Gilbert Kaplan's stunning new performance of the Second on MCA Classics to show us how the piece really should go.

Mr. Kaplan, a successful magazine publisher, conducts only this work, and has devoted his life to its history. The two-CD set (MCAD2-11011, digital, 84 min.) is handsomely packaged and crammed full of information. The book with the first CD includes 45 pages of essays written by Kaplan; the book with the second features pertinent Mahler letters.

But all this would all be pointless if the performance were inferior. Happily, it is a bracingly eccentricity-free reading from beginning to end. I don't consider it the best ever, but no serious Mahler fan can afford to be without it. Kaplan knows how to draw on his musicological research to give us not only a grandiose, but an informed, reading of this ever-remarkable score.

The best concert performance I have ever heard of the Second Symphony was Leonard Bernstein's, about six years ago. Yet the most mannered and mangled concert reading I've encountered was again Bernstein's, heard earlier this month. His recent DG recording, taped live in 1987 (DG, digital, 423 395-2, 2-CD, 94 min.), falls somewhere in between.

In all three of these performances, the New York Philharmonic played superbly, giving the conductor everything he asked for. But the 1987 recording lacks the fleet excitement and throb of his first New York Philharmonic recording, now inexplicably in record-label limbo. (His inferior London Symphony Orchestra performance was the one included in the CBS CD reissue of the cycle.) Though the '87 reading has moments of magnificence, they are mixed so frequently with intrusive mannerisms that the recording makes for an unsatisfactory listening experience.

The new, not-yet-complete Bernstein cycle, taped live, is also curiously uneven. The first release, the Seventh Symphony with the New York Philharmonic, is extraordinary. The Ninth, with the Concertgebouw, is considerably less so. The Fifth, taped in 1987 with the Vienna Philharmonic (DG, digital, 423 608-2, 75 min.), is impressive - expansive, but never bloated. The schizophrenic nature of the Scherzo has rarely been better captured.

There are more liberties in Bernstein's new account of the First (DG, digital, 427 303-2, 56 min.), but again, this is a persuasive, electrifying performance that asks us to forgive the peculiar moments in light of the magnificent totality. The Concertgebouw plays splendidly for him here.

On Bernstein's new Fourth (DG, digital, 423 607-2, 57 min.), the same orchestra outdoes itself. The first three movements of this recording should clearly establish it as the best Fourth available - giving us the hint of diabolical darkness behind all the apparent good humor, and capturing it in glorious sound. Alas, then comes the fourth movement, which Bernstein has given to a boy alto rather than a true soprano. Helmut Wittek does admirably, but it is all wrong. Why couldn't Bernstein and DG have offered a performance with a true soprano, and kept the movement with Master Wittek as an interesting, perhaps even valuable, appendix?

Finally, I must note that Carlo Maria Giulini's titanic reading of the Ninth Symphony has been stunningly transferred to mid-priced CD (DG Galeria, analog, 423 910-2, 423 910-2, 2-CD, 89 min.). It shares, along with the CD-only Herbert von Karajan/ Berlin Philharmonic version, my top billing for recorded Ninths and is another indispensable addition to any Mahler collection.