Prolific and inexpensive, audio technologies have revolutionized culture. Easy to produce, easy to duplicate, easy to operate, it is sound that brought the world together; that made planet earth feel smaller through the second half of the twentieth century. Audio technologies changed humankind's way of receiving and processing information, effecting our reasons for reading and writing and therefore our attitiude towards learning and education. Nineteenth and early twentieth century education was dominated by those who could read. Audio technologies broke that monopoly. There is much of interest to know about sound and audio technologies. Search the contents of each icon to understand this technology.