This comprehensive case study of a systematic shift in object expression provides insight into the construal of a class of two-place activity verbs in the history of French and proposes that a change in the prepositional system underlies the shift. The book focuses on nineteen verbs of helping and hindering whose single internal object shifts from indirect to direct object during the 15th and 16th century. It describes how these verbs are distinguished from all other verbs that take indirect objects in French and explains why only their indirect object was the target of change. Troberg offers a detailed examination of the data to show that contrary to previous approaches to the problem, the shift was neither random nor a result of low-level analogical changes. An important outcome of the study links the shift in object expression to other changes in the grammar at the end of the Middle French period. The author argues that the loss of the syntactically derived Path meaning, available to simple prepositions in the earlier stages of French, not only brings about the decisive shift in object expression, but also triggers the loss of a number of resultative secondary predicate constructions at the same time.