Syngas generation by oxidative or steam reforming of hydrocarbons and oxygenates now attracts a lot of attention of researchers in the fields of heterogeneous catalysis and chemical engineering due to its tremendous importance for energy generation and synfuels production. This book reviews results of the long-term research of the international team of scientists aimed at development of efficient processes of syngas generation in structured catalytic reactors. Multiscale integrated optimization approach is applied throughout of this work including design of nanocomposite active components stable to coking and sintering; developing heat-conducting monolithic substrates comprised of refractory alloys and cermets (honeycomb and microchannel structures, gauzes etc) and procedures of their loading with active components; design and manufacturing of several types of pilot-scale reactors (with the radial or the axial flow direction) equipped with unique liquid fuel evaporation and mixing units and internal heat exchangers. Extended tests of these reactors fed by fuels from C1 to gasoline, mineral and sunflower oil have been carried out with a broad variation of experimental parameters including stability tests up to 1000 h. Performance analysis has been made with a due regard for equilibrium restrictions on the operational parameters. Transient behavior of the monolith reactor during start-up (ignition) of the methane partial oxidation to synthesis gas was studied and analyzed via mathematical modeling based upon detailed elementary step mechanism. This provides required bases for theoretical optimization of the catalyst bed configuration and process parameters.