“But Didn’t We Have Fun? An Informal History of Baseball’s Pioneer Era, 1843-1870,” by Peter Morris; 286 pages; $27.50)

Any institution that endures in American culture passes through an interesting transitional period – the time when it straddles the line between an informal practice and a more structured, formal activity.

This is particularly true in the United States of the 1800s, which began the century as a nation of oral traditions and ended it in a golden age of ascending standards and practices. By the time 1900 rolled around, the seeds of America as we know it had been planted and were growing.

Even baseball had its transcendent moment, the time when – thanks to some avid players who wanted to write down the rules and all play the game the same way – the sport took momentous steps from being a pastime with a lowercase “p” to the National Pastime we know today.

That is the period with which Peter Morris concerns himself in “But Didn’t We Have Fun?” And, except for an occasional proclivity toward getting lost in the weeds, he brings to life those early days with solid research and wonderful anecdotes.

This is a rich tapestry of lore – of personalities and teams long forgotten, of early community games called “town ball” and “patch ball” and “sock ball.” Morris populates his pages with such ballclubs as the Empire Club of St. Louis, the wonderfully named Brooklyn Pastimes and even, believe it or not, the Jackson (Mich.) Unknowns.

Sweeping away the Abner Doubleday founding myth entirely, Morris parcels out the credit for baseball to many knowns and even more unknowns. He uncovers and plunders many treasure troves of primary sourcing, particularly reminiscences of early baseball days by aging players remembering from the vantage point of the 1890s and early 1900s.

The tale he weaves feels like the adult equivalent of a schoolboy’s summer afternoon: What field can we find? What should we use for bases? Are those trees in the way? Does it matter that my bat is just a big rough stick? And, most important, where on earth can we find a baseball?

As the pages turn, professional baseball comes together before our eyes, and a bunch of diverse tributaries of proto-baseball flow, year by year, into the mighty, formalized, commercial river that we know today as the National Pastime.

Morris’ efforts will be of most use and interest to hardcore baseball fans, but anyone interested in microhistory – how culture plays out on a very small canvas, in this case a ballfield – will find something to like in “But Didn’t We Have Fun?”

“It wasn’t the rules that were really important; what mattered were the rituals and customs,” Morris writes. And that’s the heart of his book – the notion that what we understand and appreciate today as canon, as American tradition, was once fresh as a summer afternoon and just being written.

In the era after Barry Bonds and Mark McGwire, it’s a refreshing reminder.