Many scholars and judges attempt to harmonize legal practices of contracting with the social practice of promising in ordinary life. This article explores an alternative genealogy of contract in traditional social practices that track many of contract's core norms: taking vows and oaths. Without denying that promissory morality infiltrates modern contract, contract-as-vow-or-oath can expose by way of a supplementary account why some contract rules work as they do and can take some pressure off of a more unitary promissory theory in (...) justifying, explicating, and reforming contract law. (shrink)