This text tells the story of the communications revolution spurred by the American postal system and the challenge it posed for American business, politics and cultural life. From its establishment in 1775 to the commercialization of the electric telegraph in 1844 the system caused a revolution no less far-reaching then the subsequent revolutions associated with the telegraph, telephone or computer.

《计算机科学导论（原书第3版）》是大学计算机相关专业的基础课教材，涉及计算机科学的各个方面。本书着重讲解基本概念而不是数学模型和技术细节，通过大量的图表和演示范例讲解计算机科学的基础知识；每章后面的关键术语、小结和练习有助于读者掌握和复习知识要点。本书内容丰富，通熟易懂，既适合当作大专院校的计算机基础课教材，也可作为一般的计算机基础入门读物。