While I'm always interested in reading about the great industrial designers of the 20th century, this is a rather peculiar take on the subject, as the late Christopher Innes chose to focus on Norman Bel Geddes and Joseph Urban due to how they came out of theater, the author's great interest.
What mars the book a little for me is that I'm not sure that Innes was aware of what he did not know, starting with granting Bel Geddes rather too much credit for the "Streamline" look, though he was certainly one of the great populizers of the style. Frankly, in the late 1920s/early 1930s, you might say that "streamlining" was in the air, as designers were taking notes from a new generation of airplanes and ocean liners for which streamlining was a matter of necessity as velocities increased.
Other examples of background ignorance that I tripped over like rocks is, one, when Innes describes "Starwars" as a "brilliant revival of the genre," apparently not being aware that there was a significant number of people who saw the work of George Lucas as an artistic regression after the hard won respectability of the "New Wave" of science fiction in the late 1960s/early 1970s. Also, when talking about Otto Koller, who collaborated on the aviation concepts of Bel Geddes, is described as "the former chief engineer for the German Luftwaffe," Innes apparently being unaware that the German air arm of the Great War was called the Deutsche Luftstreitkräfte. Finally, to give one last example, Innes goes out of his way to somewhat low-ball the importance of men such as Harley Earl and Raymond Loewy, in his urge to build up the importance of Bel Geddes.
What this means is that while Innes had many interesting insights to offer, I really don't trust this book, and I would recommend "Norman Bel Geddes Designs America" (edited by by Donald Albrecht) as a more measured overview of the man's work. This is to be followed by "Streamliner" (written by John Wall) as good introduction to Raymond Loewy's life and work. As for other commentary on Joseph Urban, I have no great suggestions.
Given the option, despite my reservations, I could give this a rating of 3.5.