Over the last several hundred years, the recitation of Havineinu, an abridged version of the daily prayer usually recited in pressing situations, has functionally ceased. This study addressed the legal analysis used to explain that change. Though the shift in perspective has been gradual, the book argues that the resulting profound change in the interpretation of halachic texts has had a direct influence on the understanding and the practice of Jewish law. It examines the sources and processes that have shaped the contours of Havineinu over time, exemplifying the subtle changes that occur in the development of halacha as a result of chiddush, or innovation.