JOHN D. GRESHAM is a veteran military analyst and co-author with Tom Clancy on his bestselling series of nonfiction "guided tour" books about military units, including Special Forces and Marines. H...ver maisJOHN D. GRESHAM is a veteran military analyst and co-author with Tom Clancy on his bestselling series of nonfiction "guided tour" books about military units, including Special Forces and Marines. He lives in Virginia.ver menos