Thomas H. Davenport 
Virtuous Pagans [PDF ebook] 
Unreligious People in America

This book, first published in 1991, examines the unreligious of America. Most sociologists of religion viewed religious belief and behaviour as having strong positive function for individual well-being — with the implicit assumption that unreligious individuals would lack meaning in life. This book applies statistical approaches to modelling causality as it analyses a controversial topic in American sociology.