In the second and concluding volume of this biography, Milton Lomask devotes the heart of his narrative (three-fourths of the text) to just three years of his subject's life: from his fatal meeting with Alexander Hamilton on the field of honor in the summer of 1804 to his acquittal of charges of treason after a spectacular trial in the summer of 1807. These were the years of the so-called "Burr Conspiracy," when the personal history of this grandson of Jonathan Edwards became nearly indistinguishable from the political history of the United States. Lomask is the latest in a long line of biographers and historians who have recounted this episode, which for dramatic appeal and colorful cast of characters has few rivals in our history.

To follow Burr's odyssey through the southwestern wilderness is to enter a bewildering maze of intrigue with seemingly no path to the center, and to compose a comprehensible account of it has taxed the talents of our best historians from Henry Adams to Dumas Malone. A professional writer rather than a scholar, Lomask retells this fabulous tale with a skilled craftsman's sense of pace and direction and eye for significant detail.

The Burr Conspiracy originated in the thwarted ambitions of a man whose political career collapsed in ruins after the duel with Hamilton. Not yet 50, Burr refused to exit the stage without playing the grand role destiny had cast for him. He turned his eyes westward across the Alleghenies to the territory now vastly augmented by the recent acquisition of the Louisiana Territory.

Here in this unstable region, peopled by independent-minded frontiersmen motivated by hatred of Spain and eager to extend the boundaries of their settlements ever westward, opportunity beckoned. In 1805 Burr floated down the Ohio and Mississippi to New Orleans, stopping at various points along the way to enthusiastic receptions (westerners did not mourn Hamilton), then moving on like a triumphant monarch. By all accounts his journey was an intoxicating experience for Burr, who on his return immediately began formulating plans, seeking funds, procuring supplies and recruiting followers for a second expedition in 1806.

Precisely what his intentions were may never be known, if indeed Burr himself knew. At its most innocent level the conspiracy was nothing more than a huge land speculation in the Ouachita Valley. Even Burr's staunchest defenders agree, however, that his principal aims were military: to lead an attack upon Spanish possessions in North America, to conquer Mexico and ultimately to liberate South America. If this was his purpose, then the conspiracy embodied the fundamental expansionist impulses of Burr's countrymen, and in this sense the enterprise could be described as patriotic.

Burr's enemies insisted that the proposed expedition against the Spanish masked a traitorous design to detach the western states and territories from the United States; that Burr, aping Napoleon, meant to establish one grand empire extending from the Mississippi Valley to Mexico City and beyond.

Fantastic as such a plot seems, the separation of the West from the union was a definite possibility at the time. Republicanism as a form of government was still on trial, and whether an administration centered on the Atlantic coast could effectively extend its jurisdiction to the transmontane region remained an open question for at least a generation following the adoption of the Constitution.

Whatever its ultimate objectives, the enterprise collapsed before it had hardly begun. By his own loose and boastful talk, Burr soon excited suspicions and alarms. His undoing came when Gen. James Wilkinson, Burr's close collaborator, turned informer. Wilkinson, who for years had been a paid Spanish agent, sent Jefferson a translated copy of a coded letter said to be from Burr, evidence that led the president to seek an indictment for treason. (It was characteristic of Wilkinson that after Burr's plot was foiled he sought payment from Spain for services rendered.)

The upshot was the celebrated trial at the federal Circuit Court in Richmond, with Chief Justice John Marshall presiding. From the standpoint of constitutional law the trial is notable for Marshall's landmark decision so narrowly construing the Constitution's definition of treason that for years afterward conviction for this crime became virtually impossible.

With Burr, the accused American Catiline, President Jefferson (offstage but very much present) and Marshall as the principal players, the trial was as much high political drama as it was a judicial proceeding. Jefferson's critics have always had a field day with it, describing his pursuit of Burr as a personal vendetta and delighting in the irony of the apostle of freedom seemingly riding roughshod over civil liberties. Although this is a gross distortion of the facts, in truth the prosecution of Burr was not Jefferson's finest hour. Sympathetic as he is toward Burr, Lomask cannot resist the temptation to portray Jefferson as the heavy. Fortunately his account lacks the stridency that mars previous defenses of Burr.

The author succeeds better than anyone to date in absolving Burr of any intention to commit treason, and in so doing presents an important new piece of evidence: The coded letter that Wilkinson transmitted to Jefferson as proof of Burr's treachery now appears to have been written not by Burr but by his associate Jonathan Dayton. Lomask gives credit for this discovery to Mary-Jo Kline, whose documentary study of the letter is included in her forthcoming edition of Burr's papers.

The revelation of Dayton's authorship of the cipher letter may serve to vindicate Burr, or it may only deepen the mystery about the man and his western expedition. That letter, even if Burr had written it, does not necessarily disclose any perfidious thoughts on his part. On the other hand, there is collateral evidence that does. Controversy over the nature of the Burr Conspiracy has raged unabated since 1807, and despite Lomask's valiant efforts, there is no end to it in sight.

Although the public man understandably dominates this volume, Lomask returns to the realm of pure biography in two chapters on Burr's four-year exile in Europe and subsequent retirement to New York City, where he practiced law until his death at the age of 80 in 1836.

The private Burr that emerges from Lomask's finely drawn portrait is a sympathetic, if flawed, personality. He was an inveterate dreamer, an incurable romantic, always in need of a sense of mission to escape the boredom of quotidian existence. Despite great success at the bar, he was constantly in debt from borrowing for his endless schemes; and whenever he had funds, he was generous to a fault in bestowing money and gifts on family and friends.

Burr's most attractive quality was his devoted attention to his daughter, the lovely Theodosia, and his grandson. Their deaths, within months of each other shortly after the exile's return, were blows from which he never fully recovered. These tragic losses, coming on top of his shattered dreams, bent but did not break him. He possessed remarkable staying power and resiliency, living out his days with a certain dignity.