I really liked this book. It recounts the early history of submarine telegraph cables and their technology from the early short distance instances to the cross Atlantic efforts (at least the Anglo-American cables). The author goes on to describe how scientists had to extend existing electrical theory to understand the behavior of electricity in transmission lines.
After transoceanic telegraphy came transoceanic telephony and it's concomitant advancements in reliability, packaging, and signal processing.
And finally Telstar and some other early satellites close out the last pages of the book.
The author clearly exposes the financial, political, and technical key points of the entire story.