I was amazed by the story - both the fight to get fingerprints accepted as a means of identification (let alone crime detection) and even more the bitter struggle for the pioneer to ever get recognition in his part developing the science of fingerprinting.
I was also intrigued to realize that fingerprinting, like the French Bertillon system, were promoted and developed to have a reliable identification of criminals so that sentencing was appropriate (i.e. a hardened criminal would adopt new identities to get lighter sentences as a "first time" offender). Good book, fascinating story!