In recent times, the Internet revolution has spawned numerous innovative enterprises-virtual companies, and electronic markets. Electronic markets (or digital markets) are scalable web-based platforms for buyers, sellers, marketmakers, and brokers to carry out business transactions. Over the last two years, there has been a proliferation of such E-Markets on the web. In this thesis, we develop an E-marketplace, which we call IMAGINE (Intelligent Market with AGents and Integrative NEgotiations) that improves upon the existing state-of-the-art in several non-trivial ways. IMAGINE combines the best features of existing E-marketplaces with several innovations. The thesis describes the conceptualization, analysis, and design of IMAGINE and provides details of implementation of a prototype of IMAGINE at the Electronic Enterprises Laboratory, Department of Computer Science and Automation, Indian Institute of Science. IMAGINE is a collaborative, co-operative, intelligent E-Market that maximizes the combined utility value of the all traders involved. IMAGINE has several distinctive features: • It uses an innovative business model, which is intelligent in the sense of perceiving the nature of the market and market forces and using this market intelligence in matching buyers with sellers and in determining the prices. • It uses integrative negotiations, which make it attractive for buyers and sellers to reveal their true business interests and valuations. • A sound and robust software architecture for a web-based implementation using best practices in object technology. • Implementation of a prototype of IMAGINE has been carried out using leading edge Internet technologies such as multi-agent technology, Jini, and Javaspaces.