Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A Good Introduction to the English Language

This is an excellent brief introduction to the English language. Potter tells the story of the development of English from its Old English roots to the modern day. He also devotes chapters to English phonetics, morphology, syntax, etymology, usage, slang/dialect, names, and American/British differences. Many of the examples are dated because the book was first published in 1951, but even these dated examples provide an interesting view into the language (such as what was slang in 1950). I particularly liked the chapters on the Renaissance and on the sentence. Even the reprint is out of print, so get it used or at the library.