UNTIL the emergence of Martin Luther King Jr. as a national leader of unprecedented significance, the most influential black American in the nation's history had been Jack Roosevelt Robinson. This is a fact of history that historians prefer to ignore or dismiss, perhaps because it does not square with prevailing perceptions of "leadership." Robinson was a baseball player; as Jules Tygiel notes in Baseball's Great Experiment, baseball is outside the conventional reach of history and therefore "is not the stuff upon which successful careers in history are normally made." As the story of the civil-rights movement is now understood, the major figures of the years before King are the likes of Frederick Douglass, W.E.B. Du Bois, A. Philip Randolph and Roy Wilkins; Robinson, by contrast, though more important than any of these, is scarcely given a wink and a nod.

But Baseball's Great Experiment may well change that; the overwhelming body of evidence Tygiel has accumulated and the authority with which he presents it cannot but force the establishment--not merely the historical establishment, but also the black establishment --to re-examine and rewrite American history, to acknowledge the absolutely pivotal role that Jackie Robinson played in the battle for civil rights. Not merely is this a book that is long overdue, but it turns out to be a book that was well worth the wait; it is comprehensive, perceptive, balanced-- and into the bargain it is eminently readable, written in a plain prose that is generously sprinkled with anecdotes.

Surely everyone knows the story. On October 23, 1945, Robinson was signed to a contract by the Montreal Royals, a farm club of the Brooklyn Dodgers. The signing had been engineered by the legendary general manager of the Dodgers, Branch Rickey. On Opening Day of 1947, after spending a spectacular year with the Royals, Robinson broke major-league baseball's de facto color line by appearing in the Dodgers' starting lineup. It was a watershed in American history, the beginning of the end for "a society characterized by northern indifference and ignorance of the plight of blacks and a firmly entrenched system of racial segregation in the South." Tygiel writes:

"Baseball was one of the first institutions in modern society to accept blacks on a relatively equal basis. The 'noble experiment' thus reflects more than a saga of sport. It offers an opportunity to analyze the integration process in American life. An examination of the forces that led to Robinson's hiring, the reaction among both blacks and whites, the institutional response of the baseball establishment, and the resulting decline of the Jim Crow leagues reveals much about the United States in the 1940s and 1950s. The halting and incomplete nature of baseball's achievement notwithstanding, few other businesses have equalled its performance. The dynamics of interracial relationships among players, coaches, and managers provide rare insights into what occurs when nonwhites are introduced into a previously segregated industry."

Having thus defined the major themes of his book, Tygiel systematically sets about bringing them to life. His depiction of the pervasive segregation of American life in the late '40s is depressingly thorough, and he cuts to the quick of the moral quandary with which baseball, as a symbol of that society, found itself confronted: "If baseball was truly the national pastime, it could not exclude a tenth of the population from participation; if baseball embodied the essence of American competition and opportunity, it could not block entry to those who possessed the requisite skills to succeed." He reveals the desperate stratagems employed by the baseball hierarchy to maintain the game's all-white complexion and the far craftier tactics employed by Rickey to break the color line. He brings new drama to the familiar tale of Robinson's heroic behavior in the face of physical threats and racial insults.

But Tygiel goes far beyond the familiar. Not merely does he give us Rickey and Robinson, "one of the most remarkable relationships in sports history," but he also gives us the stories of others who "pioneered in the baseball wilderness" of the minor leagues, who "introduced interracial baseball to cities and towns throughout the nation, enduring regional variations of prejudice and discrimination while struggling to advance to the major leagues." He documents the "racism, conservatism and indifference of baseball executives" that left individual black players to their own devices in hostile minor-league communities--and that often ran directly contrary to the willingness if not eagerness of many white players to get on with the business of desegregation. He describes, too, how baseball gradually committed itself to Robinson's cause:

". . . if baseball moved slowly to protect its black athletes, its sins were at least partially understandable. No other agency in the 1950s destroyed as many racial barriers without the aid of mass protests and federal intervention. Although organized baseball did not utilize its maximum economic potential to eliminate Jim Crow practices, the very existence of interracial competition in the South established a compelling precedent. Integration, baseball demonstrated, was feasible and, at times, profitable. By the same token, the economic pitfalls of continued segregation grew apparent. These lessons were not lost on the modern prophets of a New South."

In the end the judgment on baseball, like that on America, must be mixed. On the one hand, "to many commentators baseball's 'great experiment' offered a model for the nation and the world"; Robinson himself, after his retirement, wrote a book in which he attempted to show "how integration has come to baseball and how it can be achieved in every corner of the land." On the other hand, in the words of Henry Aaron: "Baseball has done a lot for me. It has taught me that regardless of who you are and regardless of how much money you make, you are still a Negro." Yet in an imperfect world, what has happened in baseball in the past four decades takes the breath away, and it reflects no less breathtaking changes in the fabric of American life. More than anyone else, one man led the way:

"Reflecting on baseball's experiment in race relations, Jackie Robinson once asserted, 'I really believe that in breaking down the color barrier in baseball, our "national game," (Branch Rickey) did more for the Negroes than any white man since Abraham Lincoln.' Robinson may be forgiven his hyperbole. Nonetheless, the events unleashed by the historic alliance between Robinson and Rickey significantly altered American society. Within the realm of sports, opportunities hitherto closed to black athletes expanded. 'When I first see Jackie Robinson play in my country,' said his Cuban teammate Sandy Amoros, 'I say if he can do it, I can do it too.' Joe Black, now an executive with the Greyhound Corporation, stated, 'When I look at my house and when I look at the grass around my house, I say, "Thank God for Jackie Robinson." ' "

So must we all.