This book grew out of my 2002 UC Berkeley doctoral dissertation on the subject of positional neutralization and phonological typology. This being the case, all those thanked in that prior work may hereby consider themselves thanked again (even, perhaps especially, the cats). To that earlier foundation have been added new data, new discussion, even some new experimental results. Gone, I hope, are most of the errors, oversights, and imperspicuities. Since then a great many people have helped me move this work forward. First among them is Sharon Inkelas, my one-time advisor and current colleague, whose advice, help, and encouragement was indispensible in making all this happen.