This book traces the recent socio-historical trajectory of educational language policy in Arizona, the state with the most restrictive English-only implementation in the US. Chapters, each representing a case study of policy-making in the state, include: an overview and background of the English-only movement, the genesis of Structured English Immersion (SEI), and current status of language policy in Arizona; an in-depth review of the Flores case presented by its lead lawyer; a look at early Proposition 203 implementation in the context of broader educational 'reform' efforts; examples of how early state-wide mandates impacted teacher professional development; a presentation of how new university-level teacher preparation curricula misaligns with commonly-held beliefs about what teachers of language minority students should know and understand; an exploration of principals' concerns about enforcing top-down policies for SEI implementation; an investigation of what SEI policy looks like in today's classrooms and whether it constitutes equity; and finally, a discussion of what the various cases mean for the education of English learners in the state.