If you want to acquire a collection of photographs tracing the entire history of American steam locomotive development, this is the book. It is limited to builders' portraits, and has no photos of locomotives "in action". The book is chronologically organized, and photos are chosen to illustrate the different types of engines produced, with many pictures of rare and one-of-a-kind designs, like the 2-8-8-8-4T. Some engines built for foreign railroads are included, as are elevated-railway locomotives. A great picture book.