In the early 19th century, the only way to transmit information was to send letters across the oceans by sailing ships or inland by horse and coach. The book explains how the rate of information circulation increased many times over as mail systems were developed. Nevertheless, regional differences were huge. While improvements on the most significant trade routes between Europe, the Americas and East India were considered crucial, distant places such as California or Australia had to wait for gold rush to become important enough for regular communications. The growth of passenger services, especially for emigrants, also increased the number of mail sailings.