As information technology becomes more ubiquitous in our work and daily life environments, understanding contexts of activities becomes critical to enhance a foundation for human-centered design practice. This research introduces a conceptual framework for defining, representing and incorporating contexts as core information for interactive systems design. Modular Scenario Composition Method was developed as a mechanism for linking descriptive field study information and analytical aspect models representing many viewpoints involved in the system development and use processes. Design Information Framework (DIF) previously developed by the author was used as a common information platform to bridge different information representation formats including scenarios and aspect models. By combining modular scenarios and aspect models representing contexts, chains of relations between contexts, their triggering factors, and their influences on user actions can explicitly be described.