Arabic phonetics has been part of the study of Arabic language at least since the 7th century CE. The great works by Al-Khali:l and Si:bawayh are the two cornerstones of this field. The early Arab grammarians knew phonetics and phonology quite well at that time, but interest in phonetics has remained relatively marginal until the middle of the 20th century. Modern Western phonetics, computerized innovations and other factors enhanced Arabic phonetics especially in the last two decades. This Introduction reviews five major schools which developed Arabic phonetics in the (Classical) past: dictionary, grammar, Koran reading, philosophy, and rhetoric. These are followed by modern trends in Arabic phonetic studies: dialect descriptions, sociolinguistic studies, pure phonetic features, language acquisition and teaching, and new phonetic areas: prosody and suprasegmentals. The basic differences between the two periods lie in research motivation and methodology.