I found this less compelling than "The Demon Under the Microscope." The discovery is relatively straightforward which requires a lot of "filler" material to flesh out the book.
The science of nitrogen fixation and it's profound implications for humanity quickly draw in the reader but the plot climaxes too quickly. This creates a prolonged denouement chronicling the remainder of Haber and Bosch's lives. It really feels like three separate books--one about nitrogen fixation and two biographies.
The performance is good and the characters are interesting but the science is a bit light. I believe most readers come to a book like this expecting to learn some interesting technical details. He talks about the process, but never drills down to the chemistry.
I would recommend it to anyone interested in the protagonists' lives or science history, but I would recommend "The Demon Under the Microscope" first.