When Muhammad Ali passed away last June, he was celebrated in a manner that few people – and even fewer athletes – have ever received. He was hailed as an icon and a hero, one of the most globally beloved figures of his generation.

Amidst all that adulation, it’s easy to forget that there was a time in this country that Ali was reviled, hated for many of the same reasons for which we loved him.

Author Leigh Montville has written a chronicle of that tumultuous time. “Sting Like a Bee: Muhammad Ali vs. the United States of America, 1966-71” (Doubleday, $30) tells the story of young Ali as he confronted the realities of Vietnam, challenging his draft eligibility and denouncing the war, potentially sacrificing his career along the way.

In the late 1960s, Muhammad Ali was a brash and brilliant boxer, the heavyweight champion of the world. He was quick in the ring and quick with a quip, but there was plenty amidst the pugilistic excellence and the verbal braggadocio that many found troubling. Ali’s relationship to the extremist Nation of Islam sect – led by Elijah Muhammad – was one of the biggest; he even changed his name from Cassius Clay in order to better connect with the NOI.

But his relationship with his country truly soured in 1966, when he refused to join the military after being drafted. From that act of defiance spun numerous consequences. Ali was soon entrenched in a protracted legal fight, one in which he argued that his religion forbade his participation in a war. Those legal battles led the country’s numerous boxing commissions to withdraw his licenses, remove his titles and effectively ban him from the sport. Both sides saw civil rights ramifications as well.

Through it all, Ali acted as the flawed human he was rather than the flawless idea we remember him to be. He struggled with his faith, striving to find purpose without the sport that had been his life since childhood. He struggled financially and emotionally, professionally and personally – all while never knowing if the next court case would result in Ali getting his life back or losing a chunk of it to the penal system.

It’s remarkable to think that someone who has been written about as extensively as Muhammad Ali might have an underexplored aspect to their history, and yet here we are. This period – the dark time when the shadow of Vietnam loomed over everything Ali said or did – is one that hasn’t generated the same degree of coverage. Hindsight has significantly shifted the public’s perspectives on Ali’s actions – and not in a way that is particularly flattering to said public – so it’s no surprise that it doesn’t get as much attention.

In “Sting Like a Bee,” Montville has put together an exhaustively researched and deftly written account of that stretch. The portrait of Ali is rendered with rich, meticulous detail; it’s as thorough a portrait of the man he was in those years as you could ever hope to experience.

There were some dark moments for Ali during this time. Montville is unflinching in his recounting, but he is also unjudging; this is neither a puff piece nor a hit piece. Far from hagiography, it is simply a warts-and-all look.

There’s no doubt that Ali was a fascinating character; much of what made him fascinating – his athletic skill, his infectious energy, his wit and his faith – is brought into sharp focus by this book. It’s a bit cliché to say that you learn more about someone’s character when they’re being tested, but there’s no denying that “Sting Like a Bee” will give the reader a new appreciation for the difficulties of Ali’s journey.

“Sting Like a Bee” offers a long look at a trying time in the life of a nigh-mythic figure. Thanks to Montville, we can experience these years alongside Ali. And a moment is captured, a unique time in American history filtered through the prism of one man. The Greatest.