Short answers, pulled from the story.
Rodney William Stark (the 8th of July 1934 - the 21st of July 2022) was an American sociologist of religion who spent 32 years as a professor of sociology and comparative religion at the University of Washington before joining Baylor University in 2004. He studied religion, secularization, the growth of Christianity, anti-Catholic bias in historical writing, and rational choice theory applied to religious behavior.
The Stark-Bainbridge theory of religion, developed with William Sims Bainbridge during the late 1970s and 1980s, explains religious involvement through a framework of rewards and compensators, treating belief as a rational response to human needs that earthly life cannot always satisfy. It is regarded as a precursor to the economic approach to religion later developed by Laurence Iannaccone and others.
In The Rise of Christianity (1996), Stark argued that Christianity expanded not through mass conversions but through gradual individual conversions along social networks of family, friends, and colleagues. By comparing the spread of Christianity in the Roman Empire with LDS church growth in the 19th and 20th centuries, he showed how sustained modest growth can produce enormous numerical expansion over roughly 200 years.
Published in 1999, "Secularization, R.I.P." argued that statistical data does not support the theory that religion declines as societies modernize. Stark contended that secularization theory rests on faulty quantitative analysis and ideological preconceptions rather than on empirical evidence.
Stark addressed anti-Catholic bias most directly in Bearing False Witness (2016), which argued that prejudice has distorted historical accounts of the Crusades, the Inquisition, and Pope Pius XII's conduct during the Nazi period. He also made a historical case for the Crusades in God's Battalions (2009).
Stark's personal beliefs shifted over his lifetime. In their 1987 book A Theory of Religion, he and co-author William Sims Bainbridge described themselves as personally incapable of religious faith. By 2007, after joining Baylor University, Stark described himself as an "independent Christian" and said he had always been a "cultural Christian," adding that he had previously been best described as an agnostic rather than an atheist.