It's unprecedented in publishing history for two books tracing the spiritual roots and biographies of two living popes to be published within the same month, let alone within the same lifetimes. And in tandem, or alone, they make for extraordinary reading.

One, “Last Testament: In His Own Words,” by Pope Emeritus Benedict XVI with Peter Seewald, is the much-awaited, book-length, question-and-answer autobiography of the only modern-day pope to retire from the papacy.

While Benedict's resignation in February 2013 fueled a firestorm of speculation, and bracketed a deeply divisive chapter of Catholic Church scandal, the ex-officio pope breaks his silence here and takes on the tough questions of veteran Vatican observer and fellow German Seewald, a journalist who has recorded three other book-length interviews with the former Joseph Ratzinger.

The other tome, “Pilgrimage: My Search for the Real Pope Francis,” by Mark K. Shriver, weaves spiritual memoir with anecdotal biography. (A nephew of President John F. Kennedy, Shriver is a former Maryland state delegate representing Montgomery County.)

Despite the fact that Shriver never speaks a word with Francis, the Argentina-born Jesuit whose charisma has captured a rare global attention and rekindled the faith of many a tepid Catholic, it's the one more apt to stir the soul of its readers.

From the very first page, Seewald frames his subject as far more vulnerable than he's previously been portrayed: “Instead of red slippers, he now wore sandals like a monk. He has been blind in his left eye for many years, he remembers less and less now, and meanwhile his hearing has diminished. His body had grown very thin, but his whole demeanor was tender like never before.”

It's hard not to feel pathos for a man who once led the world's 1.2 billion Roman Catholics yet now writes a weekly homily he'll deliver to an audience of only four or five believers who file in for his Sunday sermon in the convent where he now lives.

While Benedict bats down some tough questions with a simple, “I don't remember,” he takes others straight-on, asserting that his decision to step down from the papacy was one “without internal struggle,” so great was the evidence — in his own mind — in favor of doing so.

“My hour had passed,” he says, “and I had given all I could give.”

Shriver begins his search for the “real Pope Francis” by striking a common chord: “I had been yearning for a Church I could believe in again.”

Shriver's is an anecdotal biography, one that retraces Francis' life from Buenos Aires through the Jesuit seminaries and colleges and churches where he studied, taught and most of all inspired.

Shriver hears first-person accounts of the man behind the collar.

His “theology of the people” — the belief that propels Francis to kiss the leper, wash the feet of the prostitute and answer sharp-edged critiques of those outside the church's acceptance with a simple, “Who am I to judge?” — is not some newly plucked posture but rather a way of living he's carried with him all his 79 years.

He was a seminary prefect who, on the seminarians' day of rest, woke early to clean the pigsty.

He was the cardinal who refused to ride to his installation, preferring instead to walk to the Vatican.

While this is a rich telling of the former Jorge Mario Bergoglio's life, it is more movingly a spiritual memoir that draws us deep into a knowing of this at once humble and soul-stirring rekindler of faith.

Barbara Mahany is a freelance writer whose new book, “Motherprayer,” will be published in 2017.