BOOK REVIEW : Nun Passionately Attacks Death Penalty : DEAD MAN WALKING; An Eyewitness Account of the Death Penalty in the United States <i> by Helen Prejean, C.S.J.</i> ; Random House; $21, 278 pages

Death by electrocution, as Helen Prejean pointedly reminds us in “Dead Man Walking,” is not a pretty picture.

“The force of the electric current is so powerful that the prisoner’s eyeballs sometimes pop out on his cheeks. . . . Sometimes the prisoner catches fire. . . . There is a sound like bacon frying and the sickly sweet smell of burning flesh.”

Strong words for a morning newspaper, I know, but Prejean chose to quote these words from a Supreme Court decision precisely because they are so vivid and so repugnant: “Dead Man Walking” is, among other things, an urgent and elaborate moral argument against the death penalty.

“I cannot stand by silently as my government executes its citizens,” declares Prejean. “If I do not speak out and resist, I am an accomplice.”

We should not make the mistake of regarding Prejean as a mere propagandist or her book as nothing more than a manifesto. Rather, “Dead Man Walking” is a work of confessional literature of the very highest order, an intimate meditation on crime and punishment, life and death, justice and mercy, and--above all--Christian love in its most all-embracing sense.

“I can’t accept that God has fits of rage and goes about trucking in retaliation,” she writes in contemplation of capital punishment. “I can’t accept that any group of human beings is trustworthy enough to mete out so ultimate and irreversible a punishment as death.”

Prejean is a Roman Catholic nun whose order, the Sisters of St. Joseph of Medaille, is committed to “standing on the side of the poor.” When she was asked to become a pen pal to an inmate on Death Row at the Louisiana State Penitentiary, Prejean was allowed to glimpse an inner circle of hell on Earth. “Dead Man Walking” is an uncompromising account of what she saw.

One of the Death Row inmates whom Prejean befriended, Patrick Sonnier, was convicted along with his brother of kidnaping a teen-age couple from a lovers lane, raping the woman and shooting both in the back of the head.

Prejean is a friend and advocate of the killers, but she displays no less empathy for their victims. Indeed, Prejean comes across as a woman who is so alive to the moral implications of human conduct that she simply is incapable of complacency or ease of mind.

“Have I betrayed his victims? Do I have to take sides?” she asks herself.

Prejean sees the killer as a victim, too. “Amnesty International defines torture as an extreme physical and mental assault on a person who has been rendered defenseless,” she argues to a corrections official. “That is what happened to Patrick Sonnier, isn’t it?”

Prejean recounts her experiences on Death Row in a matter-of-fact tone that manages to shock us without the slightest note of bombast. She never shrinks from the horror of what she has seen and experienced, but she never resorts to something so predictable as pathos or a play for sympathy.

At the same time, Prejean allows herself some intimate asides that give “Dead Man Walking” an unexpected richness and resonance; the book is as much a memoir as a manifesto. She is even willing to tell a funny story or two. For example, when she describes how the prison chaplain demanded that she wear a habit when visiting Death Row, Prejean is reminded of her earliest years as a nun.

“Actually, discarding the veil probably increased my life expectancy,” she writes. “As a student teacher, my veil had caught on fire from a candle during a prayer service and I had almost gone up in smoke before my wide-eyed class.”

Prejean’s argument against the death penalty draws its fire from her own fervent belief in social justice. At one point in “Dead Man Walking,” she describes the prayers that she uttered on the eve of a clemency hearing for Pat Sonnier: “God of truth, God of life, give me words, essential words, words to pierce the conscience, to turn the heart.”

I cannot say that Prejean changed my mind about the death penalty. But her words are so plain, so blunt and yet so loving and compassionate that “Dead Man Walking” succeeded in touching my heart.