There could hardly be a more provocative book title than "The Last American Hero" to examine a figure from 20th-century history. Not only might a reader wonder what the word "hero" denotes here, they may also puzzle why there can be no more heroes to follow.

John Glenn, the third American to fly in space, veteran of two wars, former senator, is certainly a fine, honorable choice for such a biography. Glenn — like Neil Armstrong, Buzz Aldrin and Sally Ride — transcends the genre of space history and is known to the general public, even if only as a vague memory of one who flew into orbit during the dawn of the space race. This is the first major book to tell Glenn's story since his death in late 2016 at age 95, so the perfect time for analysis and evaluation of his life. Author Alice George also has the chance to analyze more objectively than Glenn's own comprehensive 1999 memoir.

George's biography breezes through Glenn's busy, ever-changing career with promises to examine his life in an inspirational way, seeing him as a memorial to a more honest time before the Watergate era of national cynicism. It's a well-worn approach that historians have used to describe Glenn for almost half a century.

George makes a good case that Glenn was heroic without being perfect. Perfection is not realistic nor human — but Glenn here certainly comes close to being a hero from central casting, with a life in public service, a lifelong marriage to a woman he met as a toddler and a general sense of always trying to do the decent thing. He was confident without being cocky, combative only at moments of righteous indignation, safe and steady as a senatorial policymaker, reliable as a pilot.

One of the original Mercury astronauts, Glenn was chosen by NASA in a team of seven to fly America's first space missions. Like the others, he was surprised that this group — selected to focus on engineering test flights and medical scrutiny — became instant celebrities, feted as national heroes years before the rockets were ready to fly them. Unlike the other six, however, Glenn sensed both opportunity and responsibility, rising to the challenge of speaking as a national representative during the height of the Cold War. He captured an All-American ideal that the other, worldlier aviators did not care to exude, and George chronicles through numerous press reports how Glenn came to represent NASA and America far more than his peers and bosses ever expected.

This may go some way to explaining why Glenn's first spaceflight grabbed national attention in a way the two American missions preceding his did not. Few generally recall the third person to do something, yet Glenn is the only one the public remembers. George whisks through news clippings and later secondhand accounts of what happened to illustrate how, for a brief time, John Glenn became the person a whole nation followed in space.

The book has moments of intriguing insight. It is illuminating to see Glenn in the America of 1968, a very different place from the one that made him famous, campaigning for Bobby Kennedy on a civil rights platform. To understand Glenn's sorrow when he had to tell Kennedy's children that their father had been murdered is heartbreaking. Glenn, it seems, had changed along with the 1960s, and we glimpse the molding of the political candidate ahead, one who would run for president in the 1980s.

George's description of the Sen. Glenn of the next few decades — bland, indecisive and a dull public speaker — seems a long way, however, from the "last hero" she promised. Readers also hoping for the promised insight into Glenn's personality and a look at who he was behind the public image are unlikely to find it in this book. Times when we obtain a deeper glimpse of Glenn's character — such as how a deeply religious man felt dropping napalm on people during combat — are referenced from his memoirs.

Oft-disputed stories, such as President John Kennedy's alleged grounding of Glenn after one spaceflight, are never fully examined; rather, they are simply repeated. Glenn's wife, Annie, a fixture of his life so consistent that they almost operated as a single individual, is a ghostlike figure in this book, someone we never get to know.

In 1997, Glenn announced that he would retire from the Senate at the end of his term in 1999 and immediately set his sights on persuading NASA to fly him into space again. Glenn's reasoning — that it would allow the agency to test the effects of space on seniors — is never questioned here, although NASA's decision was based far more on political support, public excitement and the nature of heroism than on any medical results. And having moved through all of Glenn's life without ever deviating from his own recounting of it, the busy final 17 years between his memoir and his death are only hastily covered in this book's epilogue. It's a missed opportunity to tell us something new.

As an overview of a fascinating career, this book concisely shows how, despite technological leaps such as the space race, human character is what will always fascinate us most. We learn a lot about what Glenn did, but we never learn why he did those things or who he was, which would be key to what the author promised to explore. Glenn was a complex man from a complex age, far deeper and more interesting than this book suggests.

Francis French is a space historian and, with astronaut Al Worden, co-author of "Falling to Earth: An Apollo 15 Astronaut's Journey to the Moon."