This edited book brings together research investigating foundational issues relating to the generation and restriction of alternative sets from theoretical and empirical perspectives. It includes contributions from noted scholars in the field to provide theoretical arguments, opinionated perspectives synthesizing existing positions, and empirical evidence from experimentation and fieldwork in support of a theoretical framework. Alternatives have come to occupy a central place in formal semantic theory, and are referenced in notable accounts of various phenomena, including focus, negation, implicature, modality, counterfactuals, and contrastive topics, among others. More recently, experimental investigations have addressed the mental activation and availability of alternatives in sentence comprehension and memory representations, finding that alternative meanings are computed during incremental processing, and persist in memory after sentence completion for a limited amount of time. The diverse perspectives represented in this volume will serve to clarify and guide the major avenues available in future research on the topic, and the book will be of interest to graduate students and researchers in fields such as linguistics (especially psycholinguistics and experimental pragmatics), philosophy and cognitive science.