Willie Bruised and Bruising : WILLIE : An Autobiography by Willie Nelson with Bud Shrake <i> (Simon & Schuster: $18.95</i> ; <i> 320 pp., illustrated) </i>

It can be a struggle enjoying popular music these days--you’re never quite sure where the song trails off and the hype kicks in. But here’s some relief. While other best-selling musicians pose themselves as cultural saviors, at least one superstar steps back, sighs and celebrates the fact that he’s just a happy rube riding a run of good luck.

Ignore for a minute Willie Nelson’s multimillion-dollar blue-jean endorsement deal. Skip, too, his recent self-promotion on the lurid television show “Geraldo.” As spelled out in his autobiography, singer Nelson’s personal and professional life has aimed to create good music, not larger profits. When Nelson writes that he could always survive poverty as long as he had riches of songs, it carries weight. Poetry is always more powerful when coming from the heart, and once you ponder Nelson’s story, you know his warming music doesn’t spring from any cold calculations.

Which, gladly, can also be said of his folksy, anecdotal book, co-written with former sportswriter Bud Shrake. Nelson isn’t out to win new friends in these pages. Indeed, it’s a testament to his candor that many readers of “Willie” will come to discount sharply the country-music maverick’s enduring romantic image. Nelson’s music is marked by both affecting bliss (“You Were Always on My Mind”) and invigorating laments (“Angel Flying Too Close to the Ground”), but he himself can be flat-out boorish. His almost-callous chronicles of his three marriages--and his flip dismissals of infidelity--may strike some as marks of the purebred rebel, but to others, they will seem repellent.

It’s all part of his complex idiosyncrasy, which shines through any good-ol’-boy disguises Nelson may try to hide behind. “I am as simple as I look,” he writes. “I am an itinerant singer and guitar picker. I am what they used to call a troubadour.” Yet he’s much more than such one-dimensional, self-deprecating labels. He is, in fact, an enigmatic hybrid spun out of the Depression, a broken home, a variety of youthful mishaps and a lyrical talent so profound even Nelson doesn’t quite understand it.

Riding in a plane with film director Sydney Pollack, Nelson is told that the movie “Honeysuckle Rose” needs a song. Nelson picks up an envelope--or maybe an air sickness bag, since Nelson can’t remember--and scribbles:

On the road again

I just can’t wait to get on the road

again

The life I love is making music

with my friends

I just can’t wait to get on the road

again

“It was just one of those things,” Nelson recalls. “As soon as I wrote ‘On the road again,’ the rest of the words simply flowed as if someone else was moving my pen.” His instinctive ear for Western swing and riveting melodies that redefined country music has led Nelson to write, by his count, more than 2,000 songs and a string of million-selling albums. His compositions also helped carry Patsy Cline (with “Crazy”) and Faron Young (singing “Hellow Walls”) to great acclaim.

Nelson’s music, typically refined and straightforward, doesn’t really hint at the more complicated person weaving it. And his stoned, laid-back physical appearance similarly belies a quick mind and strong will. “Inside Willie’s personality is a child, and yet he’s an alleycat,” writes music promoter Tom Gresham in one of “Willie’s” many colorful testimonials, frequently the book’s best creation. “He’s been bruised, and you can see it in his face, his scars.”

Without a trace of self-pity, Nelson recounts the adversities he has strummed around both in growing up and in finding someone, anyone, who would pay him to play. Since Nelson refuses to take himself too seriously, the crash of his failures rings with comedy, not tragedy. And some of Nelson’s most fondly remembered recollections--including the smoking of a joint on the White House roof--sparkle because Nelson is as amused by his life as is his audience.

If his strange travels have had any cumulative effect on Nelson, they have etched upon him an appreciation of all the world’s possibilities. Although it was one of his earlier compositions, to this day the plain words to Nelson’s “Night Life” distinguish a man who, for all the right reasons, loves the sound of his own voice:

Listen to the blues that they’re

playin’

Listen to what the blues are sayin’

My, it’s just another scene

From the world of broken dreams

The night life ain’t a good life

But it’s my life.