George H. W. Bush is unusual among modern American presidents in that after he left the White House in 1993 he never produced his own full-scale autobiography. True, he co-wrote a book about his administration’s foreign policy with Brent Scowcroft, his national security adviser, and then allowed a collection of his letters and diary excerpts to be published. But he showed no interest in writing the kind of doorstopper others have given us, nothing on the order of “RN: The Memoirs of Richard Nixon,” “Ronald Reagan: An American Life” or Bill Clinton’s “My Life.” Even Hillary Clinton, who may yet be president and thus get her own chance to add to the genre, has already written two thick memoirs, either of which, if you accidentally dropped it on your foot, might leave you limping.

It is a measure of Bush’s shrewdness that he cooperated so extensively with Jon Meacham on “Destiny and Power,” allowing his biographer not just access to his diaries and family members but sitting for a series of interviews from 2006 to 2015. Meacham — an executive editor at Random House, a former editor of Newsweek and the author of “American Lion,” a well-told account of Andrew Jackson’s presidency that won the Pulitzer Prize in 2009 — amply rewards his subject’s trust by producing a deeply empathetic, often moving book about the former president and what Bush calls the L-word, his legacy.

How does the reader fare in this affectionate transaction between president and biographer? Surprisingly well, since Meacham’s access and lack of ideological fervor allow him to paint Bush the man in unusually subtle colors. Bush, called “41” by friends to distinguish him from his son, the 43rd president, emerges from this book as more ambitious, more anxious and far more emotional than commonly perceived. He could easily give former House Speaker John Boehner a run for his money in the Kleenex sweepstakes.

Bush, who is now 91, also comes across as an acute and often witty observer of other people’s quirks; his anecdotes of touring Asia with Bill Clinton may be the most hilarious description of 42’s charm and egotism (“He talks all the time,’’ Bush 41 notes. “He’s just shameless”) I have ever read. And thanks to Meacham’s adroit questioning, Bush drops his customary refusal to second-guess his son’s administration and offers a devastating critique of Vice President Dick Cheney, an analysis that carries special weight since Bush himself served in that office during the Reagan years.

Raised in privilege, Bush is known to be allergic to introspection, and try as he might, Meacham unearths no “Rosebud” moment that illuminates what propelled Bush throughout his career. Perhaps it really is as simple as what Bush, in his telegraphic style, tells Meacham: “My motivation’s always been goal . . . you know, to be captain.” Pressed further, Bush is not exactly expansive: “Whatever you’re in. Be No. 1.” Bush’s father, Prescott, served as United States senator from Connecticut, but Bush did not inherit the political bug so much as the itch, as Meacham puts it, “to serve, to make his mark, to be in the game.” Despite his self-effacing style, Bush never doubted he was the best man for a job, whether it was as president of a Texas oil company, a twice-elected congressman (and failed Senate candidate) or in résumé-building positions under Nixon and Gerald Ford: United States ambassador to the United Nations, America’s envoy to China and head of the Central Intelligence Agency. ...