The book presents new models of axion for the solution of the strong CP problem. The main feature of these models is the modification of the relation between the axion mass and the Peccei-Quinn(PQ) constant, with quite interesting phenomenological consequences in particular for physics of supernovae, gamma ray burst and cosmology. We have hypothesized the existence of another sector of particles and interactions, the mirror world, which is an exact copy of our world but with a larger electroweak scale. This difference also implies a different dynamics in the QCD sector that is fully discussed...