This review seeks to extend the scope of both the experimental and theoretical work carried out since I completed my 1993 review on the electronic, optical and to a laser extent, the transport properties of a variety of semiconductor quantum dots (QDs). In addition to the many advances that have been made on the topics susch as quantum confinement effects (QCE), optical and luminescence properties, energy levels, and theoretical models that where dealt with in outline then, a number of new themes have emerged. These include detailed studies on single QDs such as InAs, InP, CuCl, etc, and this became possible due to the development of several microtechniques such as scanning near field optical microscopy, SNOM or NSOM, as well as the use of improved growth procedures such as those involving MBE and the Stranski-Krastanow (SK) growth method, or by better chemical processing.