Semiconductor self assembled quantum dots have emerged as one of the simplest means of exploring and exploiting the physics and device applications of carriers and excitons in the three dimensional confinement regime. This chapter covers the epitaxial growth processes involved in the formation of self-assembled quantum dots. A number of approaches for self-ordering and positioning quantum dots using direct epitaxial growth are also developed. The electronic structures of quantum dots using capacitance and luminescence spectroscopy techniques are presented to demonstrate the analogy between the quantum dots and ‘‘artificial atoms’’. To emphasize the difference with the properties of the isolated artificial atom, the role of the quantum dot coupling to the outside environment and the importance of many-body effects on the electronic properties of the quantum dot are also discussed. Finally we give examples of several quantum dot devices that exploit some of the quantum dot electronic and optical properties. Some of these quantum dot devices could lead to the implementation of quantum computing or quantum cryptography applications.