The most well-known of the many challenges Meriwether Lewis faced in his brief life (1774-1809) were those he confronted as leader, with William Clark, of the expedition that opened the American West.

The names of the two men are linked inextricably for their remarkable accomplishments in leading their party of explorers up the Missouri River from St. Louis, across the Rocky Mountains, down the Columbia River to the Pacific Ocean, and back to St. Louis again.

Along the way they sustained themselves by husbanding their supplies and foraging for other necessities, negotiated with Indian tribes, coped with nature's uncertainties, recorded scientific data, provided medical care for the men in their party and for Sacagawea and her child, and collected plant and animal specimens for study by others.

The authors of a new biography pay scant attention to the expedition, acknowledging that others have treated it extensively. They fault what they see, however, as the "flawed assumptions and speculations" in the work of others, particularly of Stephen Ambrose, author of the best-selling "Undaunted Courage," attributing the flaws to his uncritical reliance on the journals of the expedition.

But that is not what "Meriwether Lewis" is about. Rather, independent historians Thomas C. Danisi and John C. Jackson focus on Lewis' life after his return from the expedition.

A protégé and friend of President Thomas Jefferson, Lewis was rewarded for his leadership in the expedition by being named governor of the Louisiana Territory at age 31. In this role, he faced opposition from rivals, threats from Indians, resistance to control by traders, bureaucratic obstinacy and countless other trials. While the authors credit him with some successes, they also note his inability to surmount many of the difficulties he faced.

This might lead one to say that Lewis was simply in over his head; that, as the expression goes, he had risen to his level of incompetence. But he was not an incompetent man. His travails as governor, the authors contend, were a result of circumstances beyond his control, including betrayal by others, and of his failing health, attributable to mercury-laden "medications" he took to combat increasingly serious symptoms of malarial fever.

This leads the historians to their most controversial conclusion: Lewis was not murdered, as conspiracy theorists insist, nor did he commit suicide, in depression, as Lewis scholars have generally agreed.

Rather, the authors contend — plausibly but not convincingly — that the effects of mercury poisoning caused his demise.

Danisi, of St. Louis, and Jackson, of Olympia, Wash., are prodigious and meticulous researchers. They support their theses and conclusions with seemingly relentless citations.

Unfortunately, their writing is frequently inelegant, and their story lines are sometimes hard to follow. All but the most persistent readers are likely to work their way through the early chapters, skim the later ones, skip to the book's conclusions and then set it aside.



Myron A. Marty, a professor emeritus at Drake University, lives in Monticello, Ill.