The latest offering in Princeton University Press’s splendid “Lives of Great Religious Books” series is “C.S. Lewis’s Mere Christianity: A Biography” by front-rank historian George Marsden.

Without debate, Lewis’s classic has been the most popular explanation and defense of the Christian faith the past six decades, and Marsden is just about the perfect guy to analyze this remarkable book.

“Mere” had modest sales upon its 1952 release but eventually developed quite astonishing popularity(3.5 million copies sold in English since the 21st Century began, available in at least 36 other languages). That’s a good story that many media have treated. If yours hasn’t, then the Princeton event offers the perfect peg.

This theme was so familiar that The Religion Guy’s news expectations were slim when he idly scanned a review copy. Then Marsden magic and readability kicked in and The Guy couldn’t put it down. After all, Marsden’s award-winning “Jonathan Edwards: A Life,” somehow managed to make the great Colonial theologian’s prolix writings understandable, and as intriguing as his life story.

Lewis “does not simply present arguments; rather, he acts more like a friendly companion on a journey,” Marsden says. He “points his audiences toward seeing Christianity not as a set of abstract teachings but rather as something that can be seen, experienced, and enjoyed as the most beautiful and illuminating of all realities.” 

What underlies the stunningly wide impact of “Mere Christianity”?

Marsden describes: (1) timeless truths not limited by culture, (2) common human nature that reaches readers, (3) reason put in the context of experience and affections, (4) poetic imagination, (5) the “mere” aspect, focusing on what all Christian branches believe, (6) no “cheap grace” and (7) “the luminosity of the Gospel message itself.”

“Mere” originated not as a book but brief BBC Radio talks to Britons in the pit of World War Two that were then issued as three small books.