Book excerpt: With the help of the path integration method, this book investigates the generation of dynamical mass in various four-fermion models, including models with the internal symmetry groups SU(2), SU(3), SU(5), and with CP-violation. It also explores the local SU(2)xU(1) four-fermion model with the composite Higgs boson, and shows that the four-quark interaction appears naturally with the help of the gluon propagator in the infrared region. The book also provides the mass formula for the σ-meson, the Goldberger-Treiman relation and the values of quark condensates, and proves that four-quark models describe the region between the asymptotic freedom and quark confinement. It also considers a number of quantum processes within the framework of effective chiral Lagrangians.