Fermionic mass hierarchy, mirror matter and the fourth family

The fermionic mass hierarchy in the standard model is an outstanding and a very complex problem. It can be divided into three hierarchies. The first is the mass hierarchy among the three fermionic families. The second hierarchy is within the fermionic families, and third hierarchy is among the quark mixing angles. We show that a simple and natural solution to this problem is possible within the framework of the SM gauge symmetry in a new class of models. Furthermore, we provide a theoretical justification to why the fourth family of the SM fermions must exist by proposing a novel form of the spontaneous CP breaking. This novel spontaneous CP breaking ensures that the fourth family must be mirror matter proposed by Lee and Yang in 1956. Some implications of these models to recently observed flavour anomalies in the quark-level transitions b->sll and b->c \tau \nu will also be highlighted.