Marilyn MacGruder Barnewall began her career in 1956 as a journalist with the Wyoming Eagle in Cheyenne. During her 20 years (plus) as a banker and bank consultant, she wrote extensively for The American Banker, Bank Marketing Magazine, Trust Marketing Magazine, was U.S. Consulting Editor for Private Banker International (London/Dublin), and other major banking industry publications. She has written seven non-fiction books about banking and taught private banking at Colorado University for the American Bankers Association. She has authored seven banking books, one dog book, and one work of fiction (about banking, of course). She has served on numerous Boards in her community.

Barnewall is the former editor of The National Peace Officer Magazine and as a journalist has written guest editorials for the Denver Post, Rocky Mountain News and Newsweek, among others. On the Internet, she has written for News With Views, World Net Daily, Canada Free Press, Christian Business Daily, Business Reform, and others. She has been quoted in Time, Forbes, Wall Street Journal and other national and international publications. She can be found in Who's Who in America (2005-10), Who's Who of American Women (2006-10), Who's Who in Finance and Business (2006-10), and Who's Who in the World (2008).