||Recognizing the rationale of a product family architecture (PFA) with respect to design for mass customization (DFMC), this paper discusses the fundamental issues underlying a PFA, including product information modeling, structural implications of product families, functional variety versus technical variety, class-member relationships inherent in variety, modularity and commonality, PFA design spaces, and PFA composition. The background research is reviewed in terms of product architecture and modularity, product platform and product families, and product modeling and design process models. To organize product varieties in DFMC, a PFA should be described from three different perspectives, namely the functional (as seen from customer, sales and marketing viewpoints), behavioral (as seen from the product technology or design engineer perspective) and structural (as seen from the fulfillment or manufacturing and logistic perspective). Meeting diverse customer requirements and achieving volume economy simultaneously can be best achieved by synchronizing these three perspectives. In fact, the mappings between PFA views manifest the cooperative effort among different business functions, whilst three PFA views facilitate the integration of different phases of product development.