Because It Works.
Pragmatism is solid meat for scientists.
But for philosophers it's thin gruel indeed. Feynman once remarked that unless one is able to make one's ideas understandable to college freshmen, one doesn't really understand them. The details of a scientific theory are important and typically inaccessible except to individuals with the requisite training. Hence, it is an ideal subject for a book that seeks to make important scientific and philosophical issues accessible without garbling essential technical details. Alas, Guttmann fails the Feynman Test, but his failure is instructive.