Book excerpt: A broad endeavor of solar physics is to determine from the observed radiation the structure of the solar atmosphere and the nature of the energy balance which this structure implies. A basic feature of the solar atmosphere which is still not well understood is the chromosphere-corona transition region in which, in a height of a few thousand kilometers, the temperature increases from about 10,000 degrees K at the top of the chromosphere to about 1,000,000 degrees K at the bottom of the corona. The problem investigated in this dissertation is that of the structure and heating (or energy balance) of the transition region and the role of the transition region in the structure and heating of the atmosphere as a whole. (Author).