Over the past decade the topic of energy and environment has been ackno- edged among many people as a critical issue to be solved in 21st century since the Kyoto Protocol came into e?ect in 1997. Its political recognition was put forward especially at Heiligendamm in 2007, when the e?ect of carbon dioxide emission and its hazard in global climate were discussed and shared univ- sallyascommonknowledge.Controllingtheglobalwarmingintheeconomical framework of massive development worldwide through this new century is a very challenging problem not only among political, economical, or social c- cles but also among technological or scienti?c communities. As long as the humans depend on the combustion of fossil for energy resources, the waste heat exhaustion and CO emission are inevitable. 2 In order to establish a new era of energy saving and environment benign society, which is supported by technologies and with social consensus, it is important to seek for a framework where new clean energy system is inc- porated as infrastructure for industry and human activities. Such a society strongly needs innovative technologies of least CO emission and e?cient en- 2 ergy conversion and utilization from remaining fossil energies on the Earth. Energy recycling system utilizing natural renewable energies and their c- version to hydrogen may be the most desirable option of future clean energy society. Thus the society should strive to change its energy basis, from foss- consuming energy to clean and recycling energy.

Tatsuhiro Okada has a long research career in fuel cell researches especially in polymer electrolyte fuel cells. His main interest covers characterization of polymer electrolyte membranes, anode and cathode catalysts and development of new materials and systems. Especially novel type of catalysts based on organic complexes are his recent research targets.

Masao Kaneko has been active in the research area of photoenergy conversion, artificial photosynthesis, photoelectrochemical cells, functional molecular and polymeric meta complexes, and electrocatalyses by functional molecule-coated electrodes. His recent research focuses on creation of sustainable energy from biomass under solar irradiation.

Historical Overview and Fundamental Aspects of Molecular Catalysts for Energy Conversion.- Charge Transport in Molecular Catalysis in a Heterogeneous Phase.- Electrochemical Methods for Catalyst Evaluation in Fuel Cells and Solar Cells.- Molecular Catalysts for Fuel Cell Anodes.- Macrocycles for Fuel Cell Cathodes.- Platinum-Free Catalysts for Fuel Cell Cathode.- Novel Support Materials for Fuel Cell Catalysts.- Molecular Catalysts for Electrochemical Solar Cells and Artificial Photosynthesis.- Molecular Design of Sensitizers for Dye-Sensitized Solar Cells.- Fabrication of Charge Carrier Paths for High Efficiency Cells.- Environmental Cleaning by Molecular Photocatalysts.- Optical Oxygen Sensor.- Adsorption and Electrode Processes.- Spectroscopic Studies of Molecular Processes on Electrocatalysts.- Strategies for Structural and Energy Calculation of Molecular Catalysts.- Future Technologies on Molecular Catalysts.