This volume offers a timely reconsideration of the function, content, and origin of phonological features, in a set of papers that is theoretically diverse yet thematically strongly coherent. Most of the papers were originally presented at the International Conference "Where Do Features Come From?" held at the Sorbonne University, Paris, October 4-5, 2007. Several invited papers are included as well. The articles discuss issues concerning the mental status of distinctive features, their role in speech production and perception, the relation they bear to measurable physical properties in the articulatory and acoustic/auditory domains, and their role in language development. Multiple disciplinary perspectives are explored, including those of general linguistics, phonetic and speech sciences, and language acquisition. The larger goal was to address current issues in feature theory and to take a step towards synthesizing recent advances in order to present a current "state of the art" of the field.