John Gallagher could refer to multiple individuals across various fields. In literature and journalism, for example, John Gallagher might be an author, reporter, or critic. If you are referring to the John Gallagher who is an author and journalist specializing in urban planning and architecture, he is known for his work at the Detroit Free Press and for books like "Reimagining Detroit: Opportunities for Redefining an American City," in which he explores the transformation and challenges faced by the city of Detroit. If you're asking about a different John Gallagher, such as a novelist or a specialist in another area, please provide additional context so that I can give you an accurate description.