The birth of the international telegraph system. Unfortunately it feels rather like a book-length Wired article, and has no references, so it's hard to tell where to go from here. What's there is interesting, but I spotted a couple of errors (which a year later I now can't recall the exact details of, so instead I'm going to have to leave you with a vague sense of unease).
I can, on the other hand, thoroughly recommend the 19th-century novel
Love by Ella Cheever Thayer, to which this book refers, and which I read