Some terrible what-ifs shadow the truncated career of Elvis Presley. What if he hadn't frittered away most of the '60s in lousy movies? What if he'd kicked the drugs that eventually bloated him to obesity and killed him in his bathroom? And what if he'd lived and recorded during the last quarter-century?

Elvis, of course, bears most of the blame for his disastrous career choices and grotesque exit, but he was accompanied on his trip to dissolution and beyond by some colorful hangers-on, weasels and con men. The most prominent, by far, was Col. Tom Parker, the irrepressible huckster who became his manager soon after the two met in 1955, and kept managing him right till the ugly end. When Presley fans hunt for villains, Parker is the primary suspect, and for good reason. He tightly controlled every aspect of the King's business life, from concert dates to interviews to his grueling schedule in Hollywood.

Judging from The Colonel, Alanna Nash's authoritative new biography, much of the finger-pointing is justified. No one held more sway over Presley than this rotund former carny, and if anyone could have stopped his descent or nudged him toward health and sanity, it was Parker. He had uncanny instincts for promotion and deal-making, but the Colonel all but doomed his client to long stretches of mediocrity and contributed to his demise through an addiction to quick money and an astounding lack of interest in the creative side of Elvis's life. He rarely watched the movies he pushed Presley to make, nor did he take much interest in the music. To him, Presley was a cash machine so efficient that not even death could stop it. "Elvis didn't die. The body did," he told reporters once the body was buried. "This changes nothing."

To its great credit, The Colonel never feels like an indictment, nor does it spend many of its nearly 400 pages apportioning guilt. Mostly, it is a celebration of a gargantuan character, a man who toggled to such extremes of cruelty and charm that he seems more fiction than flesh.

To a great degree, he was. Parker invented vast hunks of his own biography, fobbing himself off for years as a native West Virginian who'd risen to estimable rank in the military. The truth was richer. Parker was actually Andreas van Kujik, born in Holland, the son of a horse-stable manager. Restless and miserable at home, Dreas, as he was known to his family, boarded a ship to America and somehow sneaked into the country.

Before he left home, he might have committed murder. Nash presents circumstantial evidence implicating Parker in the stabbing death of a Rotterdam shopkeeper, whom he allegedly killed on his way out of Holland. The case is hardly conclusive, and it is formed, in part, through an exasperating barrage of rhetorical questions. ("Might she have said something that unleashed a torrent of emotion, something that drove the humiliated Andre, in a flash of anger . . . ?") But the possibility that Parker believed he was a suspect in a murder investigation could explain his deep aversion to traveling outside the country and a curious fact about Presley's career -- he never toured Europe. Even when Parker and Presley were desperate for cash in the '70s, the Colonel declined multimillion dollar dates all over the Continent, perhaps, Nash writes, because he worried that immigration authorities would unravel the secret of his true identity, which might lead to his arrest.

Once in the United States, Parker recreated himself through force of will and forgery, finding his home in the netherworld of carnivals that were crisscrossing the country. He dreamed up flim-flams by the dozens -- painting sparrows and selling them as canaries, peddling foot-long hot dogs that were nearly meatless. When he landed a job as head of the Humane Society in Tampa, he "staged a dog's 'fall' into a deep but narrow hole so he could take up a collection to hire a midget to crawl down for the 'rescue.' " He served in the military, too, though, far from rising to colonel, he went AWOL, was punished with a long stay in solitary confinement and apparently lost his mind. He spent months recuperating in Walter Reed Army Hospital, diagnosed by doctors as being in a "Constitutional Psychopathic State."

Once back to his senses and civilian life, Parker brought the quick-buck approach to show business. He never liked Presley's music, but he knew that anyone who could coax a crowd to pandemonium was a treasure. With help from RCA, he bought Elvis's contract from record producer Sam Phillips for the immense-seeming sum of $35,000. He then merchandised Elvis in ways that nobody had ever imagined. Early on, during the Presley backlash, he even sold "I Hate Elvis" pins.

Parker understood the perils of overexposure, and during Presley's years in the Army, the Colonel shooed away RCA, which wanted to stoke the Elvis bonfire with new recordings. Parker realized that, long-term, there was more to gain from retooling his prodigy as a family-friendly soldier who had faithfully served his country. Unfortunately, the sense of restraint didn't last. Presley made more than 25 movies in the '60s, sometimes at a three-a-year clip. The money was good -- for a time he was Hollywood's highest-paid star -- and the soundtracks were steady sellers. The scripts and songs, however, were laughable. The nadir was "Harem Scarum," which was shot in 18 days and required Presley to wear a turban and sing lines like "Come hear my desert serenade."

A televised special in 1968 revived interest in Presley's music, and he was soon the most lucrative act in Vegas, where his concerts initially won raves, set attendance records and earned a fortune for the International Hotel. But the triumphant years were brief. Presley grew bored, his personal life dissolved into a shambles. Depressed and worried that his hour of glory had passed, he consumed an increasingly toxic cocktail of uppers and downers as the years went on.

All the while, Parker gobbled an outrageous share of Presley's income and struck side deals and demanded consulting fees from casinos, movie studios and RCA. Asked once by a journalist if he really took 50 percent of everything Presley earned, he shot back, "No, that's not true at all. He takes fifty percent of everything I earn."

Despite this gluttony, the Colonel as rendered by Nash is an impossible character to hate. Yes, he thrived on humiliating some underlings, and he was both a pathological cheapskate and a compulsive gambler. But he never pretended to be anything other than "a snowman," as he called himself, and he never went back on his word or reneged on a deal. He also had a gentle side. He doted on his wife, and a host of former employees are quoted as saying they loved him like a father.

Nash, a feature writer at Entertainment Weekly and author of previous music biographies, is a fine guide to this supersized personality. During his life, the Colonel worked hard to cover his early tracks or obscure them in mythology, and the author clears the brush better and more thoroughly than it has ever been cleared before. She spent hours with Parker late in his life -- he died in 1987 -- and empathizes enough with the rascally codger to capture his ample charms.

For Presley fans, The Colonel does a compelling job of explaining a mystery: Why didn't Elvis fire Parker? To a degree, it was because Presley didn't want to know the details of his finances or the scale of Parker's self-dealing. But Presley was malleable because he was cripplingly insecure, and the Colonel masterfully exploited the King's abiding sense that his reign would end. Presley was controlled with steady gobs of cash and cleverly worded threats.

"We do it this way, we make money," he famously told Presley. "We do it your way, we don't make money." Elvis might have lived longer and left an even richer musical legacy, had he followed his own hunches. It is a tribute to TheColonel that we now know why he didn't. •