Book excerpt: This volume investigates the theory of the effect of static electric fields on one-electron states in. nanocylindrical and nanospherical heterolayers and quantized semiconductor films. Homogeneous external electrostatic field for all these structures has been considered as a "universal" modulating factor. For structures with radial symmetry, a study on the influence of radial static field and the electric field of a charged ring on one-electron states is presented. Chapters focusing on homogeneous field effect on low-dimensional excitonic states in the quantized films and quantum wires - in both wide bandgap and narrowband semiconductors - are also included. Other contents include calculations weak, moderate and strong electric fields, quantum-mechanical approximation and perturbation theory, the quasi-classical approximation (WKB method). Readers will benefit from the varied methodological to the subject which gives them a concrete analytical framework to solve problems related to nanoscale semiconductor design. The reference should prove to be useful to academics and professionals working in semiconductor nanoelectronics research and development.