This book offers an overview of the state of the art in the field of DeNO_x catalysis in order to focus novel orientations, new technological developments, from laboratory to industrial scale. A particular attention has been paid towards the implementation of catalytic processes for minimising NO_x emissions either from stationary or mobile sources under lean condition to meet future standard regulations of NO_x emissions. In the first part of this book, critical aspects reported in the literature which usually make difficult the achievement of efficient...