Workbook in Historical Phonology provides forty-eight problems in the areas of sound change, internal reconstruction and comparative reconstruction. Each of the three sections offers a series of problems of various lengths graded according to difficulty. There are twenty-one problems on sound change, twelve on internal reconstruction and fifteen on comparative reconstruction. The data for the problems are taken from language phyla found all over the world, such as Indo-European, Austronesian, Afro-Asiatic, Nilo-Saharan, Kartvelian, Sino-Tibetan, Uralic, and from various language phyla in the Americas. The International Phonetic Alphabet, a Distinctive Feature chart, plus several brief discussions of sound changes can be found in the Appendix.