The current book, Engineering Microplasticity and its Appli- cations, would endeavour an exploration of plasticity theory at its vary foundation. As a departure from the classical macroplasticity theory (which is overviewed on a compact manner in chapter 2 of the book), a systematic framework of microplasticity is laid down in the Part II of the book from a combined approach of solid mechanics and material science, encompassing various plastic deformation mechanisms from dislocations, twinning, shear banding, grain boundary sli- ding to transformation induced plasticity. Beside a systema- tic discussion on the constitutive formulation derived from crystalline and geological materials, other interesting sub- jects of microplasticity, like the hardening mechanisms and meso-damage theory, are also discussed in great detail. The above-mentioned prospective subjectsare depicted in concise mechanics language and by tensor notation, which could help the readers to gain not only qualitative, but quantitative understanding on various phenomena of microplasticity, as rendering necessary with the rapid progress of computational apparatus and technologies.