THERE IS a quality to the voice on this record--the voice of Sylvia Plath reading her own poetry--that can only be described as frightening. It is not just the eerieness of hearing a voice from beyond the grave, of listening to a woman expose her obsession with the subject of death three months before she takes her own life. The really scary, chilling thing about this voice is its profound bitterness--a sort of challenge to all comers that commands sympathy at the same time that it defies it, that attracts as it repels, that bores directly at some common core of human experience with a drill of inhuman strength.

It is an extraordinary voice, one that should not have been kept from the general public for so long. Plath taped this reading on October 30, 1962, three days before her thirtieth birthday, during a particularly turbulent and astonishingly creative period of her life. Separated from her husband and living on her own in London with two small children, she would rise at four every morning to work and in the month of October alone spewed forth at least 26 poems. For the past 13 years the tape has been preserved in the Woodberry Poetry Room in Lamont Library, but it was not until this year that the executor of Plath's estate--her sister-in-law Olwyn Hughes--consented to release the tape for a commercial recording.

Plath reads her poems with a relentless intensity. She seems to hurl her words at the listener, each elegantly rounded vowel like a trajectory for a gunshot-sharp consonant. Just as she tried in her poetry to use her craft and skill to "manipulate intense personal experience"--as she says in an interview included on the record--so she uses impeccable diction to give a defining framework to the raw, brute emotion in her voice.

HEARING MANY of these poems--there are thirteen in all--is a completely different experience from reading them. Plath's tone or inflection often brings out a sinister sadness that is only latent in the printed word. The well-known poem "Cut," for instance, can be read merely as a strangely detached, almost innocent investigation of an everyday occurrence; but when Plath reads it, it is savage.

What a thrill--

My thumb instead of an onion.

The top quite gone

Except for a sort of hinge

Of skin,

A flap like a hat,

Dead white.

Then that red plush.

In the more obscure "Amnesiac," the last few lines become a vicious, lingering taunt.

Oh sister, mother, wife

Sweet Lethe is my life