books.google.com - A dominating theme of the 21st Century will be the transmission and processing of information as the global network of communication channels continues to develop. The emergence of today's digital communications technology owes much to the growth of telegraphy in the 19th and 20th Centuries. The realisation...https://books.google.com/books/about/History_of_Telegraphy.html?id=k3XCkncd83AC&utm_source=gb-gplus-shareHistory of Telegraphy