The historian Jacques Barzun once wrote, “Whoever wants to know the heart and mind of America had better learn baseball.” That notion probably goes double for Canada and hockey.

The argument will be bolstered Tuesday with the publication of “A Great Game: The Forgotten Leafs and the Rise of Professional Hockey,” written by Stephen J. Harper, the Canadian prime minister. The book is no mere collection of thoughtful essays or policy recommendations, as one might expect from a sitting politician.

Rather, it is a 320-page scholarly history of an obscure period in Toronto hockey more than a century ago, with footnotes and bibliography. It is as if President Obama published a densely researched study of early basketball in Chicago.

“A Great Game” took Harper nine years to research, write and publish. For the last seven of those years, he has been the prime minister, raising the inevitable question: Doesn’t he have more important things to do with his time?