Soon they’ll be throwing forearm shivers over at the Ravens’ training camp, so we can all put forlorn Orioles baseball behind us. Almost in anticipation of the new football season, an early copy arrives of Baltimore freelance writer Jack Gilden’s riveting new book, “Collision of Wills: Johnny Unitas, Don Shula, and the Rise of the Modern NFL” (University of Nebraska Press).

It’s a reminder of a time when the Baltimore Colts were among the classiest teams in all of NFL history (and the Orioles were still among baseball’s classiest.) Also, it’s a revealing look behind the scenes of one of the game’s most idolized players, and one of its most triumphant coaches – and how the two men won with remarkable consistency despite their sheer contempt for each other.

It’s a mark of our changing journalism that nobody in that decade, starting in 1963, reported the tension between the two key figures on that ballclub. Shula was a control freak who wanted to call the offensive plays. Unitas was the game’s brightest star, and a brilliant, seasoned play-caller, who resented anyone telling him how to run his offense.

Unitas was the last of a breed when quarterbacks figuratively drew pass patterns in the dirt. Shula was the uninvited visitor from a mechanized future that would evolve into robotic quarterbacks receiving plays dictated into their helmets.

What’s more, Unitas had won two NFL championships under Weeb Ewbank, who treated him in a fatherly fashion. Unitas loved him for that. Shula was a screamer. Unitas hated him for that.

But the book’s also about more than football. It’s about the changes sweeping the country during that era – political, cultural, sexual. And Gilden not only interviews football players and family members of the era’s Colts, but he talks to the great journalist Gay Talese for his perspective on the country.

(Point of full disclosure: Gilden quotes me a few times in the book, and says some nice things about me in his acknowledgements.)

But the book needs no special help. Gilden’s a hometown guy who’s done his homework, and he’s written with style and clarity, and he’s covered an era of Baltimore football that’s generally overlooked.

It was Unitas and Ewbank’s team that won back-to-back championships, including the fabled “Sudden Death” game in 1958 that paved the way for pro football to become the nation’s sectarian religion.

That team’s been covered so thoroughly that we’ve overlooked Shula’s clubs. But they were utterly remarkable. In seven years here, Shula’s teams won more than three-quarters of their games. Take away the first and last years, and they were a stunning 55-and-12 over five years. In two of those years, they lost a combined total of two games.

In that time, Shula was one of the game’s holy trinity of coaches – Green Bay’s Vince Lombardi and Dallas’ Tom Landry were the others – and Unitas was shining up the legend he’d already sculpted.

But they didn’t win a Super Bowl under Shula, and that’s what many of us remember, and it’s why he and the Colts and embittered owner Carroll Rosenbloom ultimately parted ways.

Gilden brings the great years, and the bitter big-game defeats, and the off-the-field bitterness, into print in a way we’ve never seen it before. It’s a brave book, for he’s taking some of the romantic sheen off a team we survivors of that era still recall with gee whiz affection.

It’s an honest book, a book for grownups to read. And, in telling the story, he brings texture to the era and a greater understanding of the struggles we thought we knew about, and those we didn’t even suspect.

A former Baltimore Sun columnist and WJZ-TV commentator, Michael Olesker is the author of six books, including “The Colts’ Baltimore: A City and its Love Affair in the 1950s” (Johns Hopkins University Press).