"Polymer Reaction Engineering VI", held in Halifax, Canada in May 2006, is the 6th in a continuing series of triennial conferences on emerging technologies and scientific advancements in the area of polymer reaction engineering. Key topics discussed included reaction engineered nanocomposites and nanoparticles, production of polymers with controlled architectures, online monitoring of polymerization systems, measurement and modeling of polyolefin particle growth and reactor hydrodynamics, and polymerization process intensification via novel reactor design. The contributions submitted for this special issue of Macromolecular Symposia provide a cross-section from the conference, reflecting the developing trend of applying reaction engineering principles and skills not only to improvement of polymerization processes, but also to the design and development of new materials.