"Lectures on the Science of Language" by F. Max Müller

Friedrich Max Müller was a German-born philologist and Orientalist, who lived and studied in Britain for most of his life. He was one of the founders of the western academic disciplines of Indian studies and religious studies. His expertise put him in a unique position to be able to write a book on the science of linguistics. From how language is developed empirically to its theoretical stages, he describes how language isn't static. Much like other scientific fields, it's ever-evolving.