Innovations in Catalysts Design -- Recent Advances in Ruthenium Catalysts for Alkene Metathesis -- New N-Heterocyclic Carbene Ligands in Grubbs and Hoveyda-Grubbs Catalysts -- Ruthenium-Indenylidene Complexes Bearing Saturated N-Heterocyclic Carbenes: Synthesis and Application in Ring-Closing Metathesis Reactions -- Building Indenylidene-Ruthenium Catalysts for Metathesis Transformations -- The Influence of the Anionic Counter-Ion on the Activity of Ammonium Substituted Hoveyda-Type Olefin Metathesis Catalysts in Aqueous Media -- Ruthenium Catalysts Bearing Carboxylate Ligand -- Ruthenium-Arene Complexes Derived from NHC?CO2 and NHC?CS2 Zwitterionic Adducts and Their Use in Olefin Metathesis -- Mono- and Bimetallic Ruthenium-Arene Catalysts for Olefin Metathesis: A Survey -- Mesoporous Molecular Sieves Based Catalysts for Olefin Metathesis and Metathesis Polymerization -- Binary and Ternary Catalytic Systems for Olefin Metathesis Based on MoCl5/SiO2 -- Concepts and Challenges in Sustainable Chemicals Synthesis -- Ring-Closing Metathesis Synthesis of Medium and Large Rings: Challenges and Implications for Sustainable Synthesis -- Functionalisation of Vinylsubstituted (Poly)Siloxanes and Silsesquioxanes via Cross-Metathesis and Silylative Coupling Transformations -- The Olefin Metathesis Reactions in Dendrimers -- Alkene Metathesis and Renewable Materials: Selective Transformations of Plant Oils -- Recent Applications of Alkene Metathesis in Fine Chemical Synthesis -- Probing the Mechanism of the Double C-H (De)Activation Route of a Ru-Based Olefin Metathesis Catalyst -- A Comparison of the Performance of the Semiempirical PM6 Method Versus DFT Methods in Ru-Catalyzed Olefin Metathesis -- Mechanism of Gold-Catalyzed Cycloisomerization of Enynyl Esters -- Carbonyl-Olefin Exchange Reaction and Related Chemistry -- Activation of Cycloolefin Metathesis by Ultrasonic Irradiation -- Microwave-Assisted Olefin Metathesis -- New Materials by Metathesis Polymerization and Related Chemistry -- Acyclic Diene Metathesis (ADMET) Polymerization of Bis(4-pentenyl) dimethylstannane and Bis(4-pentenyl) diphenylstannane with an Electrochemically Activated Catalyst System -- A Selective Route for Synthesis of Linear Polydicyclopentadiene -- Tuning Product Selectivity in ROMP of Cycloolefins with W-Based Catalytic Systems -- [RuCl2(p-Cymene)]2 Immobilized on Mesoporous Molecular Sieves SBA-15 as Catalyst for ROMP of Norbornene -- Behavior of Silyl-Containing Norbornenes in the Conditions of Addition Polymerization -- New Applications of Ring-Opening Metathesis Polymerization for Grafting Alkylene Oxide-Based Copolymers. An outstanding international scientific event in the field of metathesis chemistry, the NATO ASI "Green Metathesis Chemistry: Great Challenges in Synthesis, Catalysis and Nanotechnology" has been recently organized in Bucharest, Romania (July 21- August 2, 2008). Numerous renowned scientists, young researchers and students, convened for two weeks to present and debate on the newest trends in alkene metathesis and identify future perspectives in this fascinating area of organic, organometallic, catalysis and polymer chemistry with foreseen important applications in materials science and technology. Following the fruitful practice of NATO Advanced Study Institutes, selected contributions covering plenary lectures, short communications and posters have been compiled in this special volume dedicated to this successful convention on green metathesis chemistry. General interest was primarily focused on relevant "green chemistry" features related to all types of metathesis reactions (RCM, CM, enyne metathesis, ADMET and ROMP). Diverse opportunities for green and sustainable technologies and industrial procedures based on metahesis have been identified. Largely exemplified was the utility of this broadly applicable strategy in organic synthesis, for accessing natural products and pharmaceuticals, and also its ability to fit in the manufacture of smart and nanostructured materials, self-assemblies with nanoscale morphologies, macromolecular engineering.