Barbara H. Partee has played a central role in developing the now-flourishing field of formal semantics, bringing the formal semantic approach developed by logicians together with a linguistically sophisticated account of the syntax of natural languages. She has continued to be a major contributor to semantics, offering general ideas that have helped to clarify the character of the enterprise as well as imaginative and persuasive detailed analyses. Compositionality in Formal Semantics is a collection of Partee's papers that have been influential in the field but are not all readily available, and includes a new introductory essay in which Partee reflects on how her thinking and the field of semantics have developed over the past 35 years. This collection is invaluable both for understanding the history and evolution of the field and for its contribution to ongoing research.