As the world begins to mourn the death of Ronald Reagan, numerous media outlets are paying tribute to the 40th president’s political and professional achievements. But what about Reagan’s spiritual legacy? His commitment to Christianity has been questioned and debated over the years, yet his son, Michael Reagan, wrote in April 2004: “My father is a godly man. He loves God. When he decided to run for president, he didn't do it to raise himself up, to be admired, or to have others think he was great. ... He did it out of duty. He thought God had called him to run for president.”
For anyone interested in exploring this intriguing aspect of the former president’s life, a handful of recent books delve into Reagan’s faith.
Author Paul Kengor writes, “Ronald Reagan was a deeply committed Christian –and contrary to the charges of critics, his faith wasn't just a private matter.” In his 2004 book, God and Ronald Reagan, Kengor explored 
Reagan's religious faith and its impact on his political life. After reviewing Reagan's public and private statements and writings, and conducting extensive interviews with Reagan intimates (including Casper Weinberger, Ed Meese, and many others), Kengor concluded that the “guiding principle of this American hero's political philosophy was his quiet but rock-solid Christian faith.”
Kengor addresses the two reasons some Christians have criticized Reagan's religious commitment: his failure to attend church regularly as President and Nancy Reagan's involvement with astrology. While examining these matters seriously, Kengor shows why they don't get to the heart of Reagan's true religious perspective, which was more fully and accurately expressed by two seminal events.
First was the attempt on his life in 1981, after which he wrote: "Whatever happens now I owe my life to God and will try to serve Him every way I can." The second was his trip to the Soviet Union in 1988, during which he confounded his atheist hosts by peppering his public statements with religious references and spoke out strongly for religious freedom.
Publishers Weekly wrote of God and Ronald Reagan: “More devotional than scholarly, Kengor's treatment emphasizes the ex-president's affinities with evangelical Protestantism; Reagan ‘invited Christ into his life,’ acknowledged God's ‘special plan’ for him, believed in end-times prophecy and even had his presidency foretold by the Holy Spirit during a prayer circle."
Author Mary Beth Brown also found that the secret ingredient to Reagan’s successful presidency was his deep Christian faith. In her 2004 book, Hand of 
Providence: The Strong and Quiet Faith of Ronald Reagan, Brown focuses on Reagan’s “deeply felt Christian beliefs,” and showing how it was faith that guided Reagan along his distinguished career and led him to his unprecedented success.
With the support of Reagan's own words and writings, and first-hand interviews with family, friends, and co-workers, Brown makes a strong case for Reagan’s devotion to God.
According to the publisher's description, Hand of Providence will "help point others to the Cross of Jesus Christ – a cause that was near and dear to President Ronald Reagan's heart."
Michael Reagan wrote in the forward: “Dad often shared with me about the discussions he had with Billy Graham while spending time with him and how much he admired his work. Even now, with his ever failing health, there is a certain peace that comes from him, and knowing one day we will be re-united brings peace to me.
“I hope this book not only brings you a better understanding of who Ronald Reagan is, but deepens your commitment to the Lord. The greatest gift my father ever gave me was the simple knowledge that I will see him in heaven one day. I pray you are there with us.”
Reagan's God and Country by Tom Freiling (2000) is an inspirational collection of quotes by the president and stories about him that reveal his strong religious convictions. Readers will learn that Reagan believed in 
America's Christian roots, championed the struggle of good versus evil, advocated prayer and fasting, defended the rights of the unborn, celebrated strong family values, upheld the virtue of patriotism and supported prayer in schools and more.
Freiling said in a 2000 author interview that his motivation in writing the book was to offer “an unbiased, factual record of President Reagan's moral compass. Not since Lincoln had a President addressed spiritual issues, yet most of his critics disparage his strong religious convictions. This book gives the truth behind the question: Was Reagan a Christian?”
For more about these books:
Hand of Providence: The Strong and Quiet Faith of Ronald Reagan by Mary Beth Brown
Reagan's God and Country by Tom Freiling
God and Ronald Reagan by Paul Kengor