Not really mystery, because the book starts from the idea that everyone already knows Crippen is a murderer. What makes the book so enjoyable is that the true crime segments breaks up the sometimes tedious timeline of Marconi's long struggle, and in turn, Marconi's various adventures break up the very long marriage of Crippen and his wife.
A crime more than a hundred years old isn't disturbing to me, I can read about it with equanimity. And I'm interested in the development of technologies, but I wouldn't have bothered to read a separate book on each of those topics.
Library copy