“Edge of Eternity: Book Three of the Century Trilogy”by Ken Follett (Dutton, 1,098 pgs., $36)

On the night of Aug. 8, 1974, many Americans gathered before their television sets to watch Richard Nixon announce his intention to resign as president of the United States. That moment is part of “Edge of Eternity,” the last and fattest installment in Ken Follett’s 20th-century trilogy. And for him, the political is always very personal. So a man and a woman sit watching Nixon’s fall. They have been platonic friends for years. They cheer, and then they start kissing and wind up having fantastic sex. (Duration: half a page out of 1,098.) This is Follett’s favorite way to keep history interesting.

He has a limited lineup of other methods. And yet he has already drawn readers through the trilogy’s first two installments of global upheaval. “Fall of Giants” swept through the Russian Revolution, the struggle for women’s suffrage, the upstairs-downstairs outrages perpetrated by Britain’s male aristocracy, the verboten love affair between an Englishwoman and a German spy, the new world opening to immigrants fleeing Europe for the United States and President Woodrow Wilson’s worries about bringing America into World War I. That was tricky business, since “He kept us out of war” had been Wilson’s 1916 second-term campaign slogan.

To illustrate this, Follett created five families — Russian, English, Welsh, German and American — whose fates personalized historical events. Some of these fictitious characters had a way of being conveniently positioned very, very close to power; one American is on hand to awaken Wilson during a nighttime crisis and see him emerge from his bedroom wearing pajamas and a dressing gown. Throughout the series, real leaders of nations and movements have had an uncanny way of confiding their most personal thoughts to Follett’s handy aides and flunkies.

The first book was the most satisfyingly soap-operatic, with empires at stake and readers close to the action. The second, “Winter of the World,” covers World War II and is necessarily more shocking. One of its most indelible scenes involves two Germans, Rebecca, 13, and Carla, a generation older, surrounded by vicious Russian troops. In an act of terrible courage, Carla persuades the soldiers to gang rape her but leave Rebecca alone.

After the war

Carla and Rebecca are alive and well as “Edge of Eternity” begins. The year is 1961. They live in an East Germany that has not yet been walled off from the West. Rebecca’s life takes an early gut punch when she learns that her husband, Hans, is a member of the East German secret police and married her only to spy on her family. Since people in these books tend to be either very good or very bad, Hans will pop up during the next thousand pages to torment Rebecca’s relatives now and then.

Follett quickly equates East Germans’ loss of freedom with the situation of blacks deprived of civil rights in the American South. Whatever else one might make of this comparison, it introduces George Jakes, the mixed-race Harvard student whose grandfather, Lev, fled Russia in the first volume (and whose father, a white senator, likes George but doesn’t acknowledge paternity). George is a terrific character, and it’s not even a stretch when Follett makes him central to important historical moments. This book’s description of what happens to a bus full of Freedom Riders (George among them) in Alabama is authentically terrifying. Its descriptions of George’s heroism sound credible, too.

George, later a lawyer, winds up as the obligatory black face (or so he sees it) in Attorney General Robert F. Kennedy’s inner circle. Meanwhile, another of the book’s black characters winds up as one of President John F. Kennedy’s favorite girlfriends. The details of the president’s romancing come straight from Mimi Alford’s 2012 tell-all, “Once Upon a Secret,” right down to his fondness for rubber ducks in the bathtub. But it is one of Follett’s trademark maneuvers to link George’s destiny with this woman’s heartbreak on the day she has to be told that “my Johnny,” as she thinks of him, has been shot.

Follett is harshly critical of the Kennedys’ true commitment to civil rights, especially when that commitment became a political liability. But he never lets a political discussion bog down for very long. Over in the Kremlin, the highly placed Dimka Dvorkin (grandson of the first book’s firebrand Bolshevik) manages to be at the side of Nikita Khrushchev and every Russian leader to follow him, keeping readers informed about how Communist policies are working out. But he, too, has oft-described troubles with women to break up all that Politburo chatter. And he has risen to the role of mentor by the time a bright young reformer named Gorbachev comes along.

Up to the brink

Also touched on here, pretty feebly: the evolving youthquake culture that began in the mid-’60s and peaked by the end of that decade. This book distributes space so unusually that Follett is nearly halfway through it before he gets past 1963; he devotes almost 200 pages to that year alone. But two cousins, a German and a Briton, form a rock band that’s supposed to be good, and there are unconvincing observations about the Hamburg club scene. Beatles albums are also dutifully mentioned. A long chapter on 1968 covers the tumultuous events of that year, which are enough to jolt George out of politics, at least for a while; the Vietnam War is seen at its worst. The Nixon flameout, the stirrings of a new conservatism and the Iran-contra fiasco all get their due. Follett makes a point of treating Ronald Reagan’s rousing statement “Mr. Gorbachev, tear down this wall!” more as a grandstanding aside than a moment of glory. The book has strong opinions about why Communism collapsed, too.

“Edge of Eternity” does end on the brink. Its 2008 epilogue has the same people who watched so much other history unfold on television now watching Barack Obama’s election-night victory speech, which makes perfect sense in terms of the timeline Follett has chosen. A child asks: Why is an old man in the group so moved? The simple truth: “It’s a long story.”