Efforts to use existing trade agreements to build a larger regional agreement face many challenges. This book considers this problem with reference to ASEAN's current agreements with key partners and the interest to build the Regional Comprehensive Economic Partnership (RCEP). The analysis of the options is framed by a focus on the use of supply chains in international business. Issues considered include those related to reductions in tariffs, trade facilitation, the treatment of investment and of services and the definition of rules of origin. The work is informed by case studies of supply chains in automobile and electronics, and in a professional service sector. The book provides a set of priority actions for better progress in taking a bottom-up approach to building RCEP.