Material and Geometrical Instabilities in Nonlinear Elasticity provides an overview of the cutting-edge solutions to complex nonlinear instability problems. It starts by outlining basic theory and examples, providing a seamless introduction to instabilities associated with electro-mechanical materials, before moving on to more advanced topics based on nonlinear continuum mechanics and dealing simultaneously with the physical interpretation and the mathematical computations required to handle the analyses. Early chapters look at fundamental concepts such as definitions of instability, differences between material and structural/geometrical instability, and the basic tools of continuum theory within nonlinear elasticity. Coverage then progresses into more complex topics such as incremental deformations, variational approaches, cylindrical and spherical geometries, helical buckling, and piecewise homogeneous and coupled field deformations, providing examples and real-world applications of each.