LOS ANGELES — As Benedict XVI celebrates his 86th birthday on April 16, the author of a new book on the legacy of the retired pope says his humility largely inspired the work.

“I was ... fond of Benedict because he was a truly humble man,” Charles Coulombe, author of The Legacy of Pope Benedict XVI, told Catholic News Agency April 15.

“He was kind of shy and retiring, but he was willing to re-invigorate the trappings of the papacy, not for his own benefit, but for that of the office. And that’s true humility.”

The book, released in March, discusses the Church and the office of the papacy, gives a biographical sketch of Benedict’s life and addresses the reforms which the Pope undertook during his pontificate.

“It’s a good, quick introduction to both the Church and the papacy for those who don’t know anything about it, and it will be useful for those trying to figure out the areas in which (Pope Francis’) papacy will be facing challenges,” he said.

The Los Angeles-based author and historian said he was inspired to write it because he considered Benedict to have been “the best pope I’ve lived under.”

Coulombe is most fond of Benedict because his work seemed particularly to “reflect what people in parishes and dioceses were living through in their Catholic lives.”

While acknowledging that the other popes since Paul VI have had their own strengths and accomplishments, Coulombe says that Benedict’s care for such issues as the appointment of bishops was what “really concretely affects the life of the individual Catholic at the end of the day.”

“Benedict seems to understand that if you’re a believing Catholic, it’s been pretty tough.”

Coulombe described living through a period dominated by the “hermeneutic of rupture” — a view that sees a fundamental break between the Church as it existed before and after the Second Vatican Council in the 1960s, and of which Benedict spoke in his first Christmas address to the Roman Curia

He said that the bishop emeritus of Rome was the “first authoritative individual” to address the problem “in which the average Catholic lives.”

Benedict’s 2005 Christmas address to the Roman Curia, in which he defined the “hermeneutic of continuity,” is the key to understanding his pontificate, Coulombe said.

Among the four key areas of concern for him was the breach between the Church of the present and that of the past, which Benedict sought to heal with this interpretive lens.

The other three areas which Benedict’s reform focused on, said Coulombe, are a “cleaning house” — or, as he wrote in his book, “cleansing of the aberrations that have grown up within her" — as well as "reunion with other Christian bodies” and “addressing the great powers of this earth on behalf of the faith.”

These are areas in which Benedict began or continued reformation, and much remains for Pope Francis to continue with.

“None of the areas Benedict worked in were ‘solved,’” Coulombe said.

As Pope Francis’ pontificate continues, he concluded, “this Pope, and his successor and his successor will have to deal with them.”

Coulombe’s new work, released last month, is available in several e-book formats from Diversion Books for $4.99.