To provide a more direct mapping of business process specifications to software implementations, the next generation of enterprise workflow systems must move away from a procedural execution style and towards an event-driven model that monitors and controls the business process in accordance with a periodically changing set of stored business contracts, intra-organizational policies, and legislative requirements. It is the thesis of this dissertation that a crucial and hitherto neglected, aspect of electronic commerce application development techniques and tools is the analysis, modelling, storage, and interrogation of the business and contractual provisions that drive workflow applications. Extant systems for event monitoring business rules, policy-based management, contracting, and workflow execution do not directly represent, store, enact and enforce the subtle and often-times conflicting contractual and regulatory provisions contained in business requirements specifications. Explicit treatments of fundamental legal conceptions such as obligations, permissions, and powers are absent from conventional software. Furthermore, previous work in the event-, rule-, and policy-based execution styles overlooks the early phases of system development: current approaches lack guidelines to allow analysis to transform English-language specifications of contracts, policies, laws, and regulations into a structured form suitable for direct input into an implementation environment, making seamless transition through the system development life cycle a far distinct dream. In order to address these issues, this dissertation presents a novel occurrence-based development approach and execution infrastructure. The main contribution of this thesis is a method and infrastructure to create executable and queryable specifications for electronic commerce applications. A persistent history of business occurrences and associated contractual implications is kept. Multi-phase assistance for the systems development life cycle of business workflow applications is provided: we propose an analysis method coupled with implementation support in the form of a software environment, information model, algorithms, and interfaces.