This book covers new theoretical and numerical developments in the mechanics of material forces. Conceptually speaking, common continuum mechanics in the sense of Newton – which gives rise to the notion of spatial (mechanical) forces – considers the response to variations of spatial placements of physical particles with respect to the ambient space, whereas continuum mechanics in the sense of Eshelby – which gives rise to the notion of material (configurational) forces – is concerned with the response to variations of material placements of physical particles with respect to the ambient material. Well-known examples of material forces are driving forces on defects like the Peach-Koehler force, the J-Integral in fracture mechanics, and energy release. The consideration of material forces goes back to the works of Eshelby, who investigated forces on defects; therefore this area of continuum mechanics is sometimes denoted Eshelbian mechanics.