Sports in the United States at the beginning of the 20th century offered virtually no clue about the place of sports in American life 100 years later. The World Series did not exist, a crude form of football was played primarily at eastern colleges and basketball had yet to emerge from YMCAs. Sports largely were the hobby of rich white men who preferred lawn tennis, yachting, polo and fencing. It remained for an array of catalysts--innovators, athletic heroes, entrepreneurs--to realize the possibilities in sports and begin an evolution that changed primitive pastimes into an enormous part of American culture.

Babe Ruth made Americans care about sports, putting fans into the stands and, in effect, building his own stadium--he was crucial to the development of spectator sports and sports as big business. Still, the evolution of games remained in its warm-up stage until mid-century when Jackie Robinson broke racial barriers. In 1973, Billie Jean King, 29, turned an exhibition tennis match against Bobby Riggs, 55, an event promoted as "The Battle of the Sexes," into serious gains for women in sports a year after President Nixon had signed into law Title IX, banning sex bias in college athletic programs receiving federal funds. Free agency for pro athletes and the marriage of games and television insured that money would come to dominate almost every aspect of sports.

Two athletes in particular, Muhammad Ali and Michael Jordan, transcended sports in the second half of the century, in different ways but both in part because of television.

"To me, Muhammad Ali is the sports story of the century," says Don Johnson, dean of the College of Arts and Sciences at East Tennessee State University. Johnson teaches a sports literature course and edits a journal on sports literature. "It's incredible to think of how Ali stood up to the establishment and made it deal with him on his own terms. It's incredible to think what he had to lose, and I believe he was willing to give up everything for his beliefs."

A social force in civil rights and anti-Vietnam war movements, Ali refused induction into the military for religious reasons in 1967. He had won an Olympic gold medal in 1960 and upset Sonny Liston to win the heavyweight championship in 1964. But now he was found guilty of draft evasion and sentenced to five years, remaining free on appeal. Eventually, the Supreme Court reversed his conviction. Ali's most famous ring wars remained ahead of him, but because he had been banned from boxing from 1967 to 1970 his trainer, Angelo Dundee, believes he missed much of his prime. "We never saw the best of Ali," Dundee says.

An artist on the basketball court, Jordan elevated his game to its finest times, personified sports as entertainment and retired on Jan. 13, 1999, to become an even larger commercial entity. In contrast to the early days of sports, Jordan's feats could be seen regularly on television--and those vivid images of him in action created lasting impressions. "Sports allows day-to-day heroism and what might be called the potential for transcendence," Johnson says. "We saw Michael Jordan doing things that humans should not be able to do."

The social observer Jacques Barzun once said, "Whoever wants to know the heart and soul of America had better learn baseball." But these days, one might be served as well by dropping in on an NBA game or considering the ritual of Super Bowl Sunday. Games have become part of an "entertainment package" of myriad diversions and "upscale" consumption. Television networks control the games they carry to the extent that they set starting times and interrupt the contests with commercial timeouts, serving as a reminder of how much sports has become big business.

Increasingly, we have become participants--30,000 ran in last month's 30th New York City Marathon. Much of the nation lifts weights and takes part in informal games and leagues. "Sports . . . can bring you comfort and pleasure for the rest of your life," Arthur Ashe wrote in his 1993 memoir "Days of Grace," urging participation in "life sports." "Sports can teach you so much about yourself, your emotions and character, how to be resolute in moments of crisis and how to fight back from the brink of defeat. . . . You quickly discover your limits but you can also build self-confidence and a positive sense of yourself."

One thing has remained the same about sports through the entire century: They have always been compelling. Competitions have lifted our spirits, as we know every time a game is won on a last-second shot or a home run (unless we were rooting for the losing team). Sometimes those moments simply are unforgettable, such as Bobby Thomson's home run in the bottom of the ninth inning of the third playoff game to win the 1951 National League pennant for the New York Giants over the Brooklyn Dodgers--the "shot heard 'round the world." Tragedies of all sorts have occurred in sports that remind us of our mortality. But sports have provided an almost limitless source of wonder and joy--now more than ever with so many television outlets carrying so many events. Repeatedly, we have been enthralled by the remarkable and the improbable from the time sports took root early in American life.

The athlete who attracted the most attention the earliest was Tyrus Raymond Cobb. The majority of Americans of his day never saw Ty Cobb play, but only read of his exploits in newspapers. From accounts then and later, Cobb is depicted as the most disliked player of the times. From the outset of the century, Americans were given fair warning not to automatically embrace athletes as heroes; Cobb's skills were to be admired, but his character was another matter.

In contrast to Cobb and his maniacal behavior were the gentlemanly--and deservedly beloved--pitchers Walter Johnson and Christy Mathewson. Late in his career, Johnson came out of the bullpen to be the winning pitcher in Game 7 of the 1924 World Series, the Washington Senators' only victorious Series. Baseball dominated the century's early years with the likes of Cy Young, who won his 511th and last game in 1911; 1914's "Miracle Braves" who rallied from last place in July to win the National League pennant and World Series; and Pittsburgh shortstop Honus Wagner, considered by many the best all-around early player.

Jim Thorpe played the outfield in the majors from 1913 through 1919, and was a running back in football, but gained his greatest fame as winner of the pentathlon and decathlon in the 1912 Olympics. "You, sir, are the greatest athlete in the world," King Gustav V of Sweden told him. The following year, Thorpe was stripped of his medals because he had played professionally--sandlot baseball, for a pittance. Thorpe died destitute in 1953; 39 years later the International Olympic Committee reversed itself and returned the medals to his family.

Jack Johnson's fate was worse. In 1908, he became the first African-American heavyweight champion, dismaying much of white America and setting off a search for "The Great White Hope." Jim Jeffries was it. In 1910, Johnson pounded Jeffries for 15 rounds and knocked him out. Johnson, it turned out, could be stopped only by the law; he was convicted unjustly of transporting women across state lines for prostitution and fled the country. Later he returned and served eight months in jail, spending the rest of his life conveniently ignored.

The 1913 U.S. Open golf tournament produced one of the most dramatic stories of the early century. Francis Ouimet signaled the end of British dominance and the beginning of a wider participation in the sport in the United States when he defeated England's Harry Vardon, winner of five British Opens, and Ted Ray, the game's longest hitter, at The Country Club in Brookline, Mass. Ouimet, 20, a skinny former caddie who lived near the club, clinched his victory with a 20-foot putt on the 71st hole.

Baseball thrived in the 1920s, thanks mostly to Kenesaw Mountain Landis, who became the sport's powerful commissioner in 1920; Supreme Court Justice Oliver Wendell Holmes, who granted baseball an antitrust exemption in 1922, and, on the field, Babe Ruth. Ruth's mighty home runs and ebullient personality reversed public opinion about the sport following the "Black Sox scandal," when eight White Sox players, including Shoeless Joe Jackson, were accused of throwing the 1919 World Series to Cincinnati. Jackson's demise gave rise to a national sorrow: "Say it ain't so, Joe."

After being sold by the Boston Red Sox to the New York Yankees, Ruth turned baseball into a sport of individual stars. Pitcher-turned-batter, he led the American League in slugging average every season from 1918 through 1931, with the exception of 1925, and his 60 home runs in 1927 remained a record until 1961. Ruth was the most celebrated among an array of glamorous athletes to emerge in the roaring '20s.

In boxing it was Jack Dempsey, even though he lost twice to Gene Tunney--in 1927, Tunney prevailed after getting at least 14 seconds to regain his feet after a knockdown in their battle of the long count. College football produced stars galore, among them Illinois's Red Grange, Stanford's Ernie Nevers, Minnesota's Bronko Nagurski and the Four Horsemen of Notre Dame. Charlie Paddock and Johnny Weissmuller were Olympic champions. In 1926 Gertrude Ederle swam the English Channel. Other champions included Bill Tilden in tennis, golfer Bobby Jones and Ruth's teammate, Lou Gehrig.

Knute Rockne, Amos Alonzo Stagg and Pop Warner transformed early football with original ideas, while George Halas nurtured the pro game. Rockne's Notre Dame teams dominated the 1920s.

Amateurism suffered two early setbacks when Grange turned to pro football for $100,000 in 1925--his manager, C.C. ("Cash and Carry") Pyle, was the forerunner of today's agents; and, in 1930, Jones retired after winning golf's Grand Slam.

In the 1930s, all of America celebrated the accomplishments of black athletes for the first time. Jesse Owens won four gold medals to steal the spotlight from Adolf Hitler at the 1936 Olympics in Berlin and Joe Louis knocked out Max Schmeling in the first round of their 1938 rematch, avenging an earlier defeat. Later, Jackie Robinson forced the baseball establishment to open its doors to blacks after being signed by Branch Rickey and breaking in with the Dodgers in 1947.

"These three black athletes left indelible impressions on America and the world," Ashe wrote in his definitive history of African Americans in sports, "A Hard Road to Glory." "Owens was the fastest, Louis was the strongest, and Robinson was the bravest. Each in his own way forced the country to see the folly of erecting barriers between the races in the athletic arena."

Baseball struggled during the Depression but new stars emerged: Jimmie Foxx, Hank Greenberg, Lefty Grove, Carl Hubbell, Dizzy Dean, Joe DiMaggio and Ted Williams. Hank Luisetti introduced the one-handed shot in basketball and liked to play a running game. Babe Didrikson won two gold medals and a silver in track and field at the '32 Olympics in Los Angeles. Don Budge became the top amateur in tennis. And Gene Sarazen sank his double eagle in 1935 to make the Masters famous. Already suffering from the disease that would bear his name, Gehrig ended his consecutive-games streak at 2,130 on May 2, 1939, in Detroit.

Nineteen forty-one was one of the most remarkable years in sports. DiMaggio hit safely in 56 straight games. Williams became the last to hit .400, with .406--he refused to sit down with his .400 on the last day and went 6 for 8 in a doubleheader. Whirlaway, ridden by Eddie Arcaro, won the Triple Crown and kept horse racing at the forefront of sports as it had been since Man o' War won 19 of 20 races in 1919 and 1920.

The end of World War II brought a golden era in sports reminiscent of the '20s. Baseball still reigned supreme with fans turning out in record numbers in both the major and minor leagues, and also the less-publicized Negro Leagues, which could boast of such greats as Josh Gibson and Satchel Paige. Ben Hogan, Sam Snead, Byron Nelson and Patty Berg increased golf's popularity. The All-America Football Conference challenged the NFL for four years; coached by Paul Brown and quarterbacked by Otto Graham, the Cleveland Browns won all four AAFC titles. Notre Dame went undefeated in football for four years, including its scoreless-tie showdown game with Army in 1946. Citation, with Arcaro, won the 1948 Triple Crown.

The '50s were a time of change in sports. Baseball franchises relocated. Football became a TV game. Basketball was revolutionized.

Dodgers owner Walter O'Malley brought the bottom line into sports by asserting that the Dodgers belonged to him, not Brooklyn, as he persuaded the Giants to move with him to the West Coast after the 1957 season.

The 1958 NFL championship game catapulted pro football to new prominence as Johnny Unitas led the Baltimore Colts to an overtime victory over the New York Giants, in the game that wed pro football and television.

At mid-century, basketball needed an innovator. Danny Biasone, owner of the Syracuse Nationals, invented the 24-second clock, speeding the action. "He should be in the Hall of Fame," says Red Auerbach, who masterminded the Boston Celtics to Yankee-like dominance.

Bill Russell and Wilt Chamberlain, Oscar Robertson, Willie Mays and Mickey Mantle, Arnold Palmer, Rocky Marciano, Sugar Ray Robinson, Maureen Connolly and Althea Gibson--athletes provided much of the electricity in the American century's quiet decade.

Black athletes emerged in the '60s: Wilma Rudolph, Bob Hayes, Bob Beamon, Tommie Smith and John Carlos, Arthur Ashe, Jim Brown, the 1966 NCAA champion Texas Western starting five, Bob Gibson, Kareem Abdul-Jabbar. In 1960, Cleveland lawyer Mark McCormack became Palmer's representative, establishing a trend toward athletes cashing in on their fame with lucrative endorsements. The '60s belonged to, among others: Pete Rozelle, who as NFL commissioner oversaw the start of the Super Bowl; Vince Lombardi, Joe Namath, Sandy Koufax, Bear Bryant, Bill Mazeroski for his World Series-winning home run and Peggy Fleming.

In the 1970s, Curt Flood set the stage for free agency. Although his challenge to the reserve clause, which bound a player to a team for life, was beaten in court, Marvin Miller, head of the players' union, challenged the reserve clause again in the 1975 free agent case of pitcher Andy Messersmith--and won. Baseball salaries skyrocketed, as they soon would in other sports.

Hank Aaron eclipsed Ruth's career home run record. Howard Cosell sounded off, his principal forum being "Monday Night Football." Roone Arledge's TV productions, including the Monday night games, infused sports with even more drama. Tragedy befell the Olympics in Munich. Secretariat completed the 1973 Triple Crown with an extraordinary 31-length victory in the Belmont.

San Francisco and Pittsburgh would win four Super Bowls, and by 1992 the Redskins had won three; Terry Bradshaw and Joe Montana and Jerry Rice and Dwight Clark, Doug Williams and Art Monk and John Riggins helped make some of those titles possible. The 1980 U.S. Olympic hockey team beat the Soviet Union en route to the gold medal. Georgetown lost and won and lost NCAA basketball title games. Baltimore woke up one morning in 1984 to find that the Colts had moved to Indianapolis during the night. In the Olympics of 1984 and '88, Carl Lewis and Jackie Joyner-Kersee established themselves as two of the century's greatest track performers. In 1989, Paul Caligiuri scored the goal that put the U.S. men's team into the 1990 World Cup and kick-started America's soccer presence of the '90s.

Pete Rose and Mike Tyson had it all, and lost it all. Cal Ripken kept on playing (except when major league baseball players struck in 1994). The summer of 1998 belonged to Mark McGwire and Sammy Sosa, and the New York Yankees. The summer of '99 belonged to the U.S. women's soccer team, and the Yankees. Ken Griffey Jr., John Elway, Jeff Gordon, Pete Sampras, Monica Seles, the Williams sisters, Tiger Woods and Lance Armstrong helped close the century.

And so will a special few who have belonged to so much of the century and grace us still with their presence. Among these are John Wooden, Auerbach, Ted Williams, Bob Feller, Marvin Miller, Big House Gaines and Eddie Robinson, Snead and Nelson, Berg and Louise Suggs, Jay Berwanger and Slingin' Sammy Baugh.