Abstract
The development of the tunable dye laser as well as other more advanced experimental techniques has recently made possible the high-resolution study of the fine structure of the highly excited Rydberg states of alkali atoms. By recognising analytically the n dependence of the energy eigenvalue of the highly excited state based on its quasi-hydrogenic character, the authors were able to analyse quantitatively all the existing experimental measurements. The qualitative aspects concerning the fine structure splitting will also be discussed.