William J. Murray's new "My Life Without God" is as scathing a portrait of an American mother as has yet appeared in print, a situation he believes necessary to give a rounded picture of the events surrounding the celebrated Supreme Court decision outlawing prayer in public schools.

It is a semi-appalling blast at his mother, Madalyn Murray O'Hair, who brought the case on his behalf. He does not hate her, he says, and dropped her a postcard from Washington saying, "Wish you were here," and signing it, "Love, Your son, Bill."

"But she hates me," he said, and he feels she is the sort of woman who cannot maintain any sort of relationship with anybody who disagrees with her.

In the book, photographs show Bill Murray as somewhat blank looking, but now at 36 he has gray-eyed, straight-looking, stocky good looks. If pictures of him as a boy and youth look rather subdued, well, his mother was a woman of uncommon spirit and determination, sufficient to cow even grown men.

Madalyn Murray O'Hair, perhaps the nation's best-known atheist, said she was aghast when she found little Bill was subject to the public prayers conducted at his school. She brought legal action, the Supreme Court thought she was correct, and held that religion in such overt exercises as public prayer had no place in schools.

O'Hair was, of course, vilified, and young Bill grew up conspicuous. He was the atheist kid on whose behalf the court acted.

No mere mortal American woman, one suspects, can be quite as wretched a creature as Murray paints his mother. His editors, as a matter of fact, he said, could not believe certain aspects of the book, "and I spent thousands of dollars video-taping what amounted to affidavits. I simply went to people and said, 'In the book I say thus and so. You were there. Please record your own recollections of that event,' and they did.

"It is the most documented autobiography in the history of literature. Because of this, her reaction has been almost nil. She cannot sue. Her only rebuttal has been to send out negative reviews she has written to various papers, making out that I am a hysterical mother-hater or something. Which is simply not true."

All the same, the word vicious occurs to one when reading it, yet Murray is as hard on himself in the book as he is on his mother. He chronicles his two marriages ending in divorce, and a long liaison with another woman, and his ungallant behavior (he decked a couple of wives with good rights to the jaw) and his problems with booze, and his years with pot and so forth.

You might ask him if his mother is as bad as he says she was, and if he cannot conceive that some form of idealism led her to fight for so unpopular a cause.

"Any idealism was directly related to her Marxist views at that time -- that religion is the opiate of the people and if religion is destroyed then people will rise to overthrow their capitalist oppressors.

"You recall she had applied for Soviet citizenship and went to Paris to plead her case. The Soviets did not accept her application.

"The question is how and why prayer was removed from schools. Sometimes people imagine a thing is done for some idealistic reason when in fact the initial cause is base, a thing done in revenge.

"She wanted to relinquish her American citizenship, she spent all her money going to Paris to seek it, she was out of cash. Then the Sun papers [of Baltimore] wrote this big thing about her, suddenly money comes in. The revenge is financed. I call this opportunism, not idealism."

Still, a Marxist can be practically, legally and morally right, surely?

"Of course," he said. "And my mother is not a Marxist now. I am not saying all atheists are Communists, and I am not saying all Communists are evil. I am simply saying that at the time my mother concerned herself with prayer in school, there was no idealistic notion on her part about the separation of church and state, not beyond the Soviet view which in the Soviet Constitution says there shall be separation of church and state.

"I think my book has a proper place in the American perspective. I'm glad I wrote it. The first printing of 55,000 copies has sold out and there is a second printing of 15,000, with a third printing of another 15,000 planned tentatively.

"The book is, first of all, a book of identification. I mean by that that there are a lot of people who grew up marked because their father was an embezzler, say, or for some other reason suffered the glare for some action they had no part of, no responsibility for.

"I hope those people will read my book and say, 'Well, Murray survived, so maybe I can.' I drank excessively, as I say in the book, and maybe readers will see in the book how I went for help, and maybe they will, too.

"The second point of the book was simply to show how the prayer case worked, what it really was, as I saw it. You may see 20 years later that things are not what they seemed to be at the time."

Until six months ago, Murray went on, he was an aviation consultant. His last work was to help form a helicopter service from downtown Houston to the city's two airports, which are 43 miles apart. He has had several offers, he said, from airline companies to join them, but for the moment he has no long-range plans.

"I have not had a day off for five months. My immediate goal is to take Jade his 5-year-old daughter by his second marriage to Florida. She loves alligators."

There came a time in Murray's life, he said, when he got fed up with himself, with his drinking and smoking, his emptiness, his hostility. He became a Christian, he recounted, joining the Southern Baptist Church.

"I go to church regularly, I take Jade to Sunday school every week. No, I don't teach, I do not consider myself competent to teach anybody. I am in a learning stage."

He has another daughter, Robin, who is close to O'Hair, he said, and whom he does not see. It was suggested to him that he himself is ample evidence that children are not formed, totally, by members of their family, and commonly change their opinions later on.

"You could get her to love you," he said rather abstractly, a bit wistful that his older daughter has no great use for him at present.

"Look, I don't want to try to make everybody a Christian. I don't want to be any Jerry Falwell. I am not knocking him here, it's simply not my thing.

"I'm an extrovert and always have been and I like getting up in front of large numbers of people and talking. I'll probably continue."

It was suggested he gets that from his mother. He grinned and said maybe so.

"As I see it, a true Christian knows he is a sinner, he does not set himself up as holier than thou. I know I do things wrong, but by the grace of God I am forgiven. I want my book to show what my life was like without God and what really went on in that prayer case. A lot of people, knowing my story, have come to me for help. My postage was $400 a month. I set up a foundation [William J. Murray Faith Foundation Inc. in Dallas] as a referral service, but when my assistant sent out an appeal for money I fired him. I don't want that."