Early in the introduction to Nancy Peterson Hill’s “A Very Private Public Citizen: The Life of Grenville Clark” (University of Missouri Press, 2014), the author writes: “It is not too big a statement to say that Grenville Clark remains one of the most important Americans that most Americans have never heard of.” The book goes on to impressively prove that point.

Born to wealth, educated at Harvard and prosperous as a Wall Street attorney, Clark proves never able to rest on already won laurels. Throughout the first half of the 20th century, he finds himself meeting and impacting important people. Along the way he hones a finely tuned sense of social justice.

Many of his early influences came from the Adirondacks and Champlain Valley. His maternal grandfather, Col. Legrand Bouton Cannon, served as vice president of the Delaware and Hudson Railroad, which controlled a veritable monopoly of transportation routes in northern New York.

Cannon ran the company’s steamboat operations on Lake Champlain. For six months every year, he lived on a large lakeside estate in Burlington. Clark spent many childhood summers there. Years later, he still found respite in the site, returning to fish, hunt and cogitate.

Cannon told young “Grenny” stories about John Brown, then brought his grandson over to the Adirondacks to see the abolitionist’s grave. The pair found the stone amid weeds and underbrush. Over the next few years, Cannon joined an effort begun by Kate Field to clear the land and preserve the spot as an appropriate memorial to Brown.

The memory likely still resonated six decades later. That’s when Clark offered both financial and advocacy assistance to a still struggling NAACP, and organized legal support for the Freedom Riders working to register voters in the American South.

Clark, like many Americans, was galvanized by the German sinking of the American steamship Lusitania in 1915. As likelihood of war increased in Europe, he joined others in his concern about American military preparedness.

After reading about student military training experiences organized by Gen. Leonard Wood, he suggested that similar sessions be held for business and professional men. The first of these took place at Plattsburgh’s army base in 1915. Attendees included corporate executives, the mayor and police chief of New York City, college professors, a former secretary of state, and a future United States senator.

Building on the success of that first Businessmen’s Camp, Clark helped found the Military Training Camps Association. This group helped publicize the businessmen’s camps in 1916 and also advocated for the concept of universal service for all young men.

In April 1917, the United States entered World War I. Now Clark and Wood lobbied for what turned out to be the all-important officers’ training sessions in 1917. At the first of these, “graduates” of the earlier Plattsburgh camps went through additional intensive instruction, equipping them to be officers for American troops fighting in Europe. Expanded nationwide, the initiative became known throughout the country as the Plattsburgh Idea. By the end of the war, nearly 100,000 men trained in such programs had served as officers in the American armed forces.

In one form or another, the Plattsburgh camps continued as late as 1941. Meanwhile, Clark helped craft the Selective Service Act of 1940. This revamped the process by which young men were entered into the country’s military forces.

Throughout World War II, Clark served as an unofficial and unpaid – but widely heeded – advisor to Secretary of War Henry Stimson and Assistant Secretary Robert Patterson (also with Adirondack ties, having been born in Glens Falls). Later, he became active in civil rights issues, and became a staunch defender for academic freedom protections for university faculties.

During his final years, he worked tirelessly for the concept of world peace through international law. He feared the United Nations would not succeed, largely because of the decision to give veto powers to major countries on the Security Council. He also expounded on the issues of civil liberties in the face of the need for heightened national security. That perplexing and complicated dilemma remains relevant today.

The author has given us a well- organized, well-researched biography of a man whose reach into important issues was continuous for over 50 years. Grenville Clark always shunned the limelight, being comfortable remaining behind the scenes. Hill’s book gives him a prominence he never sought for himself. She also reminds us all how an informed, motivated citizen can make a difference in a vital democracy.